LeetCode-in-Kotlin

Kotlin-based LeetCode algorithm problem solutions, regularly updated.

Installation

To configure your Maven project, add the following code to your pom.xml file:

<dependencies>
  <dependency>
    <groupId>com.github.javadev</groupId>
    <artifactId>leetcode-in-kotlin</artifactId>
    <version>1.24</version>
  </dependency>
  ...
</dependencies>

Gradle configuration:

implementation 'com.github.javadev:leetcode-in-kotlin:1.24'

"For coding interview preparation, LeetCode is one of the best online resource providing a rich library of more than 300 real coding interview questions for you to practice from using one of the 7 supported languages - C, C++, Java, Python, C#, JavaScript, Ruby."

• Graph Theory I
• SQL I
• Level 1
• Level 2
• Udemy
• Data Structure I
• Data Structure II
• Algorithm I
• Algorithm II
• Binary Search I
• Binary Search II
• Dynamic Programming I
• Programming Skills I
• Programming Skills II

Graph Theory I

Day 1 Matrix Related Problems

0733	Flood Fill	Easy	Array, Depth_First_Search, Breadth_First_Search, Matrix	230	97.76
0200	Number of Islands	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find, Big_O_Time_O(M*N)_Space_O(M*N)	252	95.41

Day 2 Matrix Related Problems

0695	Max Area of Island	Medium	Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find	324	24.06
1254	Number of Closed Islands	Medium	Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find	177	89.47

Day 3 Matrix Related Problems

1020	Number of Enclaves	Medium	Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find	369	76.26
1905	Count Sub Islands	Medium	Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find	866	100.00

Day 4 Matrix Related Problems

1162	As Far from Land as Possible	Medium	Array, Dynamic_Programming, Breadth_First_Search, Matrix	362	81.25
0417	Pacific Atlantic Water Flow	Medium	Array, Depth_First_Search, Breadth_First_Search, Matrix	319	100.00

Day 5 Matrix Related Problems

1091	Shortest Path in Binary Matrix	Medium	Array, Breadth_First_Search, Matrix	305	98.28
0542	01 Matrix	Medium	Array, Dynamic_Programming, Breadth_First_Search, Matrix	441	94.06

Day 6 Matrix Related Problems

0934	Shortest Bridge	Medium	Array, Depth_First_Search, Breadth_First_Search, Matrix	301	80.95
1926	Nearest Exit from Entrance in Maze	Medium	Array, Breadth_First_Search, Matrix	351	94.44

Day 7 Standard Traversal

0797	All Paths From Source to Target	Medium	Depth_First_Search, Breadth_First_Search, Graph, Backtracking	232	100.00
0841	Keys and Rooms	Medium	Depth_First_Search, Breadth_First_Search, Graph	189	69.23

Day 8 Standard Traversal

0547	Number of Provinces	Medium	Depth_First_Search, Breadth_First_Search, Graph, Union_Find	229	79.73
1319	Number of Operations to Make Network Connected	Medium	Depth_First_Search, Breadth_First_Search, Graph, Union_Find	379	83.33

Day 9 Standard Traversal

1376	Time Needed to Inform All Employees	Medium	Depth_First_Search, Breadth_First_Search, Tree	915	37.62
0802	Find Eventual Safe States	Medium	Depth_First_Search, Breadth_First_Search, Graph, Topological_Sort	511	100.00

Day 10 Standard Traversal

1129	Shortest Path with Alternating Colors	Medium	Breadth_First_Search, Graph	208	80.00
1466	Reorder Routes to Make All Paths Lead to the City Zero	Medium	Depth_First_Search, Breadth_First_Search, Graph	718	100.00
0847	Shortest Path Visiting All Nodes	Hard	Dynamic_Programming, Breadth_First_Search, Bit_Manipulation, Graph, Bitmask	164	100.00

Day 11 Breadth First Search

1306	Jump Game III	Medium	Array, Depth_First_Search, Breadth_First_Search	291	100.00
1654	Minimum Jumps to Reach Home	Medium	Array, Dynamic_Programming, Breadth_First_Search	192	100.00
0365	Water and Jug Problem	Medium	Math, Depth_First_Search, Breadth_First_Search	130	100.00

Day 12 Breadth First Search

0433	Minimum Genetic Mutation	Medium	String, Hash_Table, Breadth_First_Search	204	82.08
0752	Open the Lock	Medium	Array, String, Hash_Table, Breadth_First_Search	310	100.00
0127	Word Ladder	Hard	Top_Interview_Questions, String, Hash_Table, Breadth_First_Search	396	98.68

Day 13 Graph Theory

0997	Find the Town Judge	Easy	Array, Hash_Table, Graph	475	58.62
1557	Minimum Number of Vertices to Reach All Nodes	Medium	Graph	792	99.29

Day 14 Graph Theory

1615	Maximal Network Rank	Medium	Graph	282	100.00
0886	Possible Bipartition	Medium	Depth_First_Search, Breadth_First_Search, Graph, Union_Find	397	100.00
0785	Is Graph Bipartite?	Medium	Depth_First_Search, Breadth_First_Search, Graph, Union_Find	215	82.35

SQL I

Day 1 Select

0595	Big Countries	Easy	Database	417	56.09
1757	Recyclable and Low Fat Products	Easy	Database	1237	34.20
0584	Find Customer Referee	Easy	Database	779	43.48
0183	Customers Who Never Order	Easy	Database	712	33.67

Day 2 Select and Order

1873	Calculate Special Bonus	Easy	Database	1321	33.12
0627	Swap Salary	Easy	Database	400	51.04
0196	Delete Duplicate Emails	Easy	Database	593	94.17

Day 3 String Processing Functions

1667	Fix Names in a Table	Easy	Database	1196	61.40
1484	Group Sold Products By The Date	Easy	LeetCode_Curated_SQL_70, Database	899	40.76
1527	Patients With a Condition	Easy	Database	708	48.23

Day 4 Union and Select

1965	Employees With Missing Information	Easy	Database	1355	23.96
1795	Rearrange Products Table	Easy	Database	1027	67.57
0608	Tree Node	Medium	LeetCode_Curated_SQL_70, Database	794	48.38
0176	Second Highest Salary	Medium	Database	219	92.54

Day 5 Union

0175	Combine Two Tables	Easy	Database	473	54.97
1581	Customer Who Visited but Did Not Make Any Transactions	Easy	Database	2771	54.68
1148	Article Views I	Easy	LeetCode_Curated_SQL_70, Database	806	54.41

Day 6 Union

0197	Rising Temperature	Easy	Database	394	94.15
0607	Sales Person	Easy	LeetCode_Curated_SQL_70, Database	2142	44.56

Day 7 Function

1141	User Activity for the Past 30 Days I	Easy	LeetCode_Curated_SQL_70, Database	790	87.11
1693	Daily Leads and Partners	Easy	Database	1115	52.84
1729	Find Followers Count	Easy	Database	1228	38.04

Day 8 Function

0586	Customer Placing the Largest Number of Orders	Easy	LeetCode_Curated_SQL_70, Database	768	44.85
0511	Game Play Analysis I	Easy	LeetCode_Curated_SQL_70, Database	790	45.04
1890	The Latest Login in 2020	Easy	Database	1280	43.62
1741	Find Total Time Spent by Each Employee	Easy	Database	1101	51.40

Day 9 Control of Flow

1393	Capital Gain/Loss	Medium	LeetCode_Curated_SQL_70, Database	990	47.36
1407	Top Travellers	Easy	LeetCode_Curated_SQL_70, Database	1394	98.43
1158	Market Analysis I	Medium	Database	2470	44.76

Day 10 Where

0182	Duplicate Emails	Easy	Database	396	68.40
1050	Actors and Directors Who Cooperated At Least Three Times	Easy	LeetCode_Curated_SQL_70, Database	629	81.02
1587	Bank Account Summary II	Easy	Database	1582	52.96
1084	Sales Analysis III	Easy	LeetCode_Curated_SQL_70, Database	1881	79.36

Level 1

Day 1 Prefix Sum

1480	Running Sum of 1d Array	Easy	Array, Prefix_Sum	161	84.80
0724	Find Pivot Index	Easy	Array, Prefix_Sum	255	88.92

Day 2 String

0205	Isomorphic Strings	Easy	String, Hash_Table	278	79.96
0392	Is Subsequence	Easy	String, Dynamic_Programming, Two_Pointers	156	87.74

Day 3 Linked List

0021	Merge Two Sorted Lists	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Linked_List, Recursion, Big_O_Time_O(m+n)_Space_O(m+n)	157	92.24
0206	Reverse Linked List	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Linked_List, Recursion, Big_O_Time_O(N)_Space_O(1)	279	45.78

Day 4 Linked List

0876	Middle of the Linked List	Easy	Two_Pointers, Linked_List	136	76.52
0142	Linked List Cycle II	Medium	Top_100_Liked_Questions, Hash_Table, Two_Pointers, Linked_List, Big_O_Time_O(N)_Space_O(1)	192	63.39

Day 5 Greedy

0121	Best Time to Buy and Sell Stock	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(N)_Space_O(1)	609	94.06
0409	Longest Palindrome	Easy	String, Hash_Table, Greedy	259	60.71

Day 6 Tree

0589	N-ary Tree Preorder Traversal	Easy	Depth_First_Search, Tree, Stack	233	84.02
0102	Binary Tree Level Order Traversal	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(N)_Space_O(N)	198	95.14

Day 7 Binary Search

0704	Binary Search	Easy	Top_100_Liked_Questions, Array, Binary_Search	261	77.91
0278	First Bad Version	Easy	Binary_Search, Interactive	349	76.86

Day 8 Binary Search Tree

0098	Validate Binary Search Tree	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree, Big_O_Time_O(N)_Space_O(log(N))	190	61.62
0235	Lowest Common Ancestor of a Binary Search Tree	Medium	Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree	404	75.59

Day 9 Graph/BFS/DFS

0733	Flood Fill	Easy	Array, Depth_First_Search, Breadth_First_Search, Matrix	230	97.76
0200	Number of Islands	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find, Big_O_Time_O(M*N)_Space_O(M*N)	252	95.41

Day 10 Dynamic Programming

0509	Fibonacci Number	Easy	Dynamic_Programming, Math, Recursion, Memoization	139	82.72
0070	Climbing Stairs	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Math, Memoization, Big_O_Time_O(n)_Space_O(n)	124	71.98

Day 11 Dynamic Programming

0746	Min Cost Climbing Stairs	Easy	Array, Dynamic_Programming	171	96.76
0062	Unique Paths	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Math, Combinatorics, Big_O_Time_O(m*n)_Space_O(m*n)	118	94.65

Day 12 Sliding Window/Two Pointer

0438	Find All Anagrams in a String	Medium	Top_100_Liked_Questions, String, Hash_Table, Sliding_Window, Big_O_Time_O(n+m)_Space_O(1)	561	54.68
0424	Longest Repeating Character Replacement	Medium	String, Hash_Table, Sliding_Window	288	84.38

Day 13 Hashmap

0001	Two Sum	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Big_O_Time_O(n)_Space_O(n)	202	91.18
0299	Bulls and Cows	Medium	String, Hash_Table, Counting	254	84.82

Day 14 Stack

0844	Backspace String Compare	Easy	String, Two_Pointers, Stack, Simulation	126	98.31
0394	Decode String	Medium	Top_100_Liked_Questions, String, Stack, Recursion, Big_O_Time_O(n)_Space_O(n)	224	64.86

Day 15 Heap

1046	Last Stone Weight	Easy	Array, Heap_Priority_Queue	123	100.00
0692	Top K Frequent Words	Medium	String, Hash_Table, Sorting, Heap_Priority_Queue, Counting, Trie, Bucket_Sort	239	81.10

Level 2

Day 1 Implementation/Simulation

0202	Happy Number	Easy	Top_Interview_Questions, Hash_Table, Math, Two_Pointers	261	45.08
0054	Spiral Matrix	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Matrix, Simulation	132	95.12
1706	Where Will the Ball Fall	Medium	Array, Dynamic_Programming, Depth_First_Search, Matrix, Simulation	270	67.86

Day 2 String

0014	Longest Common Prefix	Easy	Top_100_Liked_Questions, Top_Interview_Questions, String	154	89.70
0043	Multiply Strings	Medium	String, Math, Simulation	165	96.72

Day 3 Linked List

0019	Remove Nth Node From End of List	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Two_Pointers, Linked_List, Big_O_Time_O(L)_Space_O(L)	144	96.28
0234	Palindrome Linked List	Easy	Top_100_Liked_Questions, Two_Pointers, Stack, Linked_List, Recursion, Big_O_Time_O(n)_Space_O(1)	641	79.53

Day 4 Linked List

0328	Odd Even Linked List	Medium	Linked_List	216	86.96
0148	Sort List	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Sorting, Two_Pointers, Linked_List, Divide_and_Conquer, Merge_Sort, Big_O_Time_O(log(N))_Space_O(log(N))	820	61.70

Day 5 Greedy

2131	Longest Palindrome by Concatenating Two Letter Words	Medium	Array, String, Hash_Table, Greedy, Counting	607	90.00
0621	Task Scheduler	Medium	Array, Hash_Table, Sorting, Greedy, Heap_Priority_Queue, Counting	266	98.36

Day 6 Tree

0226	Invert Binary Tree	Easy	Top_100_Liked_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(n)_Space_O(n)	233	54.90
0110	Balanced Binary Tree	Easy	Depth_First_Search, Tree, Binary_Tree	182	71.30

Day 7 Tree

0543	Diameter of Binary Tree	Easy	Top_100_Liked_Questions, Depth_First_Search, Tree, Binary_Tree, Big_O_Time_O(n)_Space_O(n)	307	43.93
0437	Path Sum III	Medium	Depth_First_Search, Tree, Binary_Tree, Big_O_Time_O(n)_Space_O(n)	403	54.12

Day 8 Binary Search

0074	Search a 2D Matrix	Medium	Top_100_Liked_Questions, Array, Binary_Search, Matrix, Big_O_Time_O(endRow+endCol)_Space_O(1)	159	74.46
0033	Search in Rotated Sorted Array	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Binary_Search, Big_O_Time_O(log_n)_Space_O(1)	151	93.77

Day 9 Binary Search Tree

0108	Convert Sorted Array to Binary Search Tree	Easy	Top_Interview_Questions, Array, Tree, Binary_Tree, Binary_Search_Tree, Divide_and_Conquer	167	80.29
0230	Kth Smallest Element in a BST	Medium	Top_100_Liked_Questions, Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree, Big_O_Time_O(n)_Space_O(n)	393	33.33
0173	Binary Search Tree Iterator	Medium	Tree, Binary_Tree, Stack, Design, Binary_Search_Tree, Iterator	563	46.91

Day 10 Graph/BFS/DFS

0994	Rotting Oranges	Medium	Top_100_Liked_Questions, Array, Breadth_First_Search, Matrix	164	82.95
0417	Pacific Atlantic Water Flow	Medium	Array, Depth_First_Search, Breadth_First_Search, Matrix	319	100.00

Day 11 Graph/BFS/DFS

0210	Course Schedule II	Medium	Top_Interview_Questions, Depth_First_Search, Breadth_First_Search, Graph, Topological_Sort	266	96.32
0815	Bus Routes	Hard	Array, Hash_Table, Breadth_First_Search	429	100.00

Day 12 Dynamic Programming

0198	House Robber	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(n)_Space_O(n)	156	92.24
0322	Coin Change	Medium	Top_100_Liked_Questions, Array, Dynamic_Programming, Breadth_First_Search, Big_O_Time_O(m*n)_Space_O(amount)	332	50.68

Day 13 Dynamic Programming

0416	Partition Equal Subset Sum	Medium	Top_100_Liked_Questions, Array, Dynamic_Programming, Big_O_Time_O(n*sums)_Space_O(n*sums)	204	98.82
0152	Maximum Product Subarray	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(N)_Space_O(1)	253	88.42

Day 14 Sliding Window/Two Pointer

0003	Longest Substring Without Repeating Characters	Medium	Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Sliding_Window, Big_O_Time_O(n)_Space_O(1)	201	87.28
0016	3Sum Closest	Medium	Array, Sorting, Two_Pointers	163	100.00
0076	Minimum Window Substring	Hard	Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Sliding_Window, Big_O_Time_O(s.length())_Space_O(1)	191	96.38

Day 15 Tree

0100	Same Tree	Easy	Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree	134	86.63
0101	Symmetric Tree	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(N)_Space_O(log(N))	153	82.35
0199	Binary Tree Right Side View	Medium	Top_100_Liked_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree	194	92.89

Day 16 Design

0232	Implement Queue using Stacks	Easy	Stack, Design, Queue	258	70.86
0155	Min Stack	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Stack, Design, Big_O_Time_O(1)_Space_O(N)	331	84.88
0208	Implement Trie (Prefix Tree)	Medium	Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Design, Trie, Big_O_Time_O(word.length())_or_O(prefix.length())_Space_O(N)	689	61.00

Day 17 Interval

0057	Insert Interval	Medium	Array	249	75.63
0056	Merge Intervals	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Big_O_Time_O(n_log_n)_Space_O(n)	334	80.67

Day 18 Stack

0735	Asteroid Collision	Medium	Array, Stack	243	100.00
0227	Basic Calculator II	Medium	String, Math, Stack	383	62.50

Day 19 Union Find

0547	Number of Provinces	Medium	Depth_First_Search, Breadth_First_Search, Graph, Union_Find	229	79.73
0947	Most Stones Removed with Same Row or Column	Medium	Depth_First_Search, Graph, Union_Find	200	100.00

Day 20 Brute Force/Backtracking

0039	Combination Sum	Medium	Top_100_Liked_Questions, Array, Backtracking, Big_O_Time_O(2^n)_Space_O(n+2^n)	226	88.89
0046	Permutations	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Backtracking, Big_O_Time_O(n*n!)_Space_O(n+n!)	188	99.00

Udemy

Udemy Integers

0412	Fizz Buzz	Easy	String, Math, Simulation	307	71.81
0136	Single Number	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Array, Bit_Manipulation, Big_O_Time_O(N)_Space_O(1)	344	83.63
0007	Reverse Integer	Medium	Top_Interview_Questions, Math	149	77.89
0009	Palindrome Number	Easy	Math	217	95.34
0172	Factorial Trailing Zeroes	Medium	Top_Interview_Questions, Math	220	67.65
0050	Pow(x, n)	Medium	Top_Interview_Questions, Math, Recursion	172	38.68

Udemy Strings

0344	Reverse String	Easy	String, Two_Pointers, Recursion	445	69.75
0014	Longest Common Prefix	Easy	Top_100_Liked_Questions, Top_Interview_Questions, String	154	89.70
0187	Repeated DNA Sequences	Medium	String, Hash_Table, Bit_Manipulation, Sliding_Window, Hash_Function, Rolling_Hash	319	79.03
0003	Longest Substring Without Repeating Characters	Medium	Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Sliding_Window, Big_O_Time_O(n)_Space_O(1)	201	87.28
0020	Valid Parentheses	Easy	Top_100_Liked_Questions, Top_Interview_Questions, String, Stack, Big_O_Time_O(n)_Space_O(n)	137	88.76
0005	Longest Palindromic Substring	Medium	Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Big_O_Time_O(n)_Space_O(n)	162	99.00
0394	Decode String	Medium	Top_100_Liked_Questions, String, Stack, Recursion, Big_O_Time_O(n)_Space_O(n)	224	64.86
0242	Valid Anagram	Easy	String, Hash_Table, Sorting	251	87.65
0049	Group Anagrams	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, String, Hash_Table, Sorting, Big_O_Time_O(n*k_log_k)_Space_O(n)	308	96.34
0151	Reverse Words in a String	Medium	String, Two_Pointers	206	98.90
0273	Integer to English Words	Hard	String, Math, Recursion	273	82.93

Udemy Binary Search

0704	Binary Search	Easy	Top_100_Liked_Questions, Array, Binary_Search	261	77.91
0033	Search in Rotated Sorted Array	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Binary_Search, Big_O_Time_O(log_n)_Space_O(1)	151	93.77
0153	Find Minimum in Rotated Sorted Array	Medium	Top_100_Liked_Questions, Array, Binary_Search, Big_O_Time_O(log_N)_Space_O(log_N)	262	60.96

Udemy Arrays

0121	Best Time to Buy and Sell Stock	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(N)_Space_O(1)	609	94.06
0283	Move Zeroes	Easy	Top_100_Liked_Questions, Array, Two_Pointers, Big_O_Time_O(n)_Space_O(1)	516	79.07
0001	Two Sum	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Big_O_Time_O(n)_Space_O(n)	202	91.18
0217	Contains Duplicate	Easy	Top_Interview_Questions, Array, Hash_Table, Sorting	719	73.49
0058	Length of Last Word	Easy	String	135	93.67
0605	Can Place Flowers	Easy	Array, Greedy	209	85.71
0122	Best Time to Buy and Sell Stock II	Medium	Top_Interview_Questions, Array, Dynamic_Programming, Greedy	197	95.10
0080	Remove Duplicates from Sorted Array II	Medium	Array, Two_Pointers	192	80.67
0189	Rotate Array	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Math, Two_Pointers, Big_O_Time_O(n)_Space_O(1)	483	86.95
0055	Jump Game	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Greedy, Big_O_Time_O(n)_Space_O(1)	332	89.35
0075	Sort Colors	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Two_Pointers, Big_O_Time_O(n)_Space_O(1)	164	64.43
0066	Plus One	Easy	Top_Interview_Questions, Array, Math	148	98.75
0238	Product of Array Except Self	Medium	Top_100_Liked_Questions, Array, Prefix_Sum, Big_O_Time_O(n^2)_Space_O(n)	669	48.96
1291	Sequential Digits	Medium	Enumeration	114	100.00
0448	Find All Numbers Disappeared in an Array	Easy	Array, Hash_Table	394	100.00
0442	Find All Duplicates in an Array	Medium	Array, Hash_Table	480	73.81
0041	First Missing Positive	Hard	Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Big_O_Time_O(n)_Space_O(n)	357	97.17
0697	Degree of an Array	Easy	Array, Hash_Table	289	84.62
0532	K-diff Pairs in an Array	Medium	Array, Hash_Table, Sorting, Binary_Search, Two_Pointers	230	84.62
0713	Subarray Product Less Than K	Medium	Array, Sliding_Window	336	92.11
1007	Minimum Domino Rotations For Equal Row	Medium	Array, Greedy	421	50.00
1306	Jump Game III	Medium	Array, Depth_First_Search, Breadth_First_Search	291	100.00
0456	132 Pattern	Medium	Array, Binary_Search, Stack, Ordered_Set, Monotonic_Stack	434	100.00
0239	Sliding Window Maximum	Hard	Top_100_Liked_Questions, Array, Heap_Priority_Queue, Sliding_Window, Queue, Monotonic_Queue, Big_O_Time_O(n*k)_Space_O(n+k)	1059	86.14

Udemy Two Pointers

0392	Is Subsequence	Easy	String, Dynamic_Programming, Two_Pointers	156	87.74
0125	Valid Palindrome	Easy	Top_Interview_Questions, String, Two_Pointers	353	52.06
0977	Squares of a Sorted Array	Easy	Array, Sorting, Two_Pointers	271	77.17
0026	Remove Duplicates from Sorted Array	Easy	Top_Interview_Questions, Array, Two_Pointers	249	67.38
0042	Trapping Rain Water	Hard	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Two_Pointers, Stack, Monotonic_Stack, Big_O_Time_O(n)_Space_O(1)	189	99.37
0015	3Sum	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Two_Pointers, Big_O_Time_O(n*log(n))_Space_O(n^2)	493	93.45

Udemy Famous Algorithm

0053	Maximum Subarray	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Divide_and_Conquer, Big_O_Time_O(n)_Space_O(1)	510	78.81
0169	Majority Element	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Sorting, Counting, Divide_and_Conquer, Big_O_Time_O(n)_Space_O(1)	460	51.25

Udemy Sorting Algorithms

0912	Sort an Array	Medium	Array, Sorting, Heap_Priority_Queue, Divide_and_Conquer, Merge_Sort, Bucket_Sort, Counting_Sort, Radix_Sort	606	98.48

Udemy 2D Arrays/Matrix

0304	Range Sum Query 2D - Immutable	Medium	Array, Matrix, Design, Prefix_Sum	1373	85.71
0074	Search a 2D Matrix	Medium	Top_100_Liked_Questions, Array, Binary_Search, Matrix, Big_O_Time_O(endRow+endCol)_Space_O(1)	159	74.46
0054	Spiral Matrix	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Matrix, Simulation	132	95.12
0048	Rotate Image	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Math, Matrix, Big_O_Time_O(n^2)_Space_O(1)	160	90.11
1572	Matrix Diagonal Sum	Easy	Array, Matrix	221	67.61
0073	Set Matrix Zeroes	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Matrix, Big_O_Time_O(m*n)_Space_O(1)	248	97.33
0056	Merge Intervals	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Big_O_Time_O(n_log_n)_Space_O(n)	334	80.67

Udemy Linked List

0114	Flatten Binary Tree to Linked List	Medium	Top_100_Liked_Questions, Depth_First_Search, Tree, Binary_Tree, Stack, Linked_List, Big_O_Time_O(N)_Space_O(N)	191	93.10
0445	Add Two Numbers II	Medium	Math, Stack, Linked_List	240	82.61
0328	Odd Even Linked List	Medium	Linked_List	216	86.96
0061	Rotate List	Medium	Two_Pointers, Linked_List	160	92.22
0024	Swap Nodes in Pairs	Medium	Top_100_Liked_Questions, Linked_List, Recursion, Big_O_Time_O(n)_Space_O(1)	149	44.20
0876	Middle of the Linked List	Easy	Two_Pointers, Linked_List	136	76.52
0142	Linked List Cycle II	Medium	Top_100_Liked_Questions, Hash_Table, Two_Pointers, Linked_List, Big_O_Time_O(N)_Space_O(1)	192	63.39
0141	Linked List Cycle	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Hash_Table, Two_Pointers, Linked_List, Big_O_Time_O(N)_Space_O(1)	223	91.85
0206	Reverse Linked List	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Linked_List, Recursion, Big_O_Time_O(N)_Space_O(1)	279	45.78
0021	Merge Two Sorted Lists	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Linked_List, Recursion, Big_O_Time_O(m+n)_Space_O(m+n)	157	92.24
0160	Intersection of Two Linked Lists	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Hash_Table, Two_Pointers, Linked_List, Big_O_Time_O(M+N)_Space_O(1)	262	83.50
0234	Palindrome Linked List	Easy	Top_100_Liked_Questions, Two_Pointers, Stack, Linked_List, Recursion, Big_O_Time_O(n)_Space_O(1)	641	79.53
0138	Copy List with Random Pointer	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Hash_Table, Linked_List, Big_O_Time_O(N)_Space_O(N)	274	80.58
0025	Reverse Nodes in k-Group	Hard	Top_100_Liked_Questions, Linked_List, Recursion, Big_O_Time_O(n)_Space_O(k)	189	67.03
0146	LRU Cache	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Hash_Table, Design, Linked_List, Doubly_Linked_List, Big_O_Time_O(1)_Space_O(capacity)	1116	97.93
0707	Design Linked List	Medium	Design, Linked_List	243	100.00

Udemy Tree Stack Queue

0144	Binary Tree Preorder Traversal	Easy	Depth_First_Search, Tree, Binary_Tree, Stack	277	37.90
0094	Binary Tree Inorder Traversal	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Tree, Binary_Tree, Stack, Big_O_Time_O(n)_Space_O(n)	152	66.67
0145	Binary Tree Postorder Traversal	Easy	Depth_First_Search, Tree, Binary_Tree, Stack	211	80.00
0102	Binary Tree Level Order Traversal	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(N)_Space_O(N)	198	95.14
0103	Binary Tree Zigzag Level Order Traversal	Medium	Top_Interview_Questions, Breadth_First_Search, Tree, Binary_Tree	176	71.62
0108	Convert Sorted Array to Binary Search Tree	Easy	Top_Interview_Questions, Array, Tree, Binary_Tree, Binary_Search_Tree, Divide_and_Conquer	167	80.29
1008	Construct Binary Search Tree from Preorder Traversal	Medium	Array, Tree, Binary_Tree, Stack, Monotonic_Stack, Binary_Search_Tree	145	100.00
0543	Diameter of Binary Tree	Easy	Top_100_Liked_Questions, Depth_First_Search, Tree, Binary_Tree, Big_O_Time_O(n)_Space_O(n)	307	43.93
0938	Range Sum of BST	Easy	Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree	356	55.36
0100	Same Tree	Easy	Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree	134	86.63
0226	Invert Binary Tree	Easy	Top_100_Liked_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(n)_Space_O(n)	233	54.90
0111	Minimum Depth of Binary Tree	Easy	Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree	525	90.51
0104	Maximum Depth of Binary Tree	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(N)_Space_O(H)	166	83.53
0110	Balanced Binary Tree	Easy	Depth_First_Search, Tree, Binary_Tree	182	71.30
0701	Insert into a Binary Search Tree	Medium	Tree, Binary_Tree, Binary_Search_Tree	311	79.03
0297	Serialize and Deserialize Binary Tree	Hard	String, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Design	475	78.85
0124	Binary Tree Maximum Path Sum	Hard	Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Depth_First_Search, Tree, Binary_Tree, Big_O_Time_O(N)_Space_O(N)	331	74.42
0098	Validate Binary Search Tree	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree, Big_O_Time_O(N)_Space_O(log(N))	190	61.62
0337	House Robber III	Medium	Dynamic_Programming, Depth_First_Search, Tree, Binary_Tree	282	84.62
0236	Lowest Common Ancestor of a Binary Tree	Medium	Top_100_Liked_Questions, Depth_First_Search, Tree, Binary_Tree, Big_O_Time_O(n)_Space_O(n)	386	45.21
0968	Binary Tree Cameras	Hard	Dynamic_Programming, Depth_First_Search, Tree, Binary_Tree	176	100.00

Udemy Trie and Heap

0208	Implement Trie (Prefix Tree)	Medium	Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Design, Trie, Big_O_Time_O(word.length())_or_O(prefix.length())_Space_O(N)	689	61.00
0745	Prefix and Suffix Search	Hard	String, Design, Trie	1638	100.00

Udemy Graph

0200	Number of Islands	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find, Big_O_Time_O(M*N)_Space_O(M*N)	252	95.41
0133	Clone Graph	Medium	Hash_Table, Depth_First_Search, Breadth_First_Search, Graph	351	60.91
0417	Pacific Atlantic Water Flow	Medium	Array, Depth_First_Search, Breadth_First_Search, Matrix	319	100.00

Udemy Dynamic Programming

0120	Triangle	Medium	Array, Dynamic_Programming	194	97.87
0118	Pascal's Triangle	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming	277	33.22
0119	Pascal's Triangle II	Easy	Array, Dynamic_Programming	157	97.27
0139	Word Break	Medium	Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Dynamic_Programming, Trie, Memoization, Big_O_Time_O(M+max*N)_Space_O(M+N+max)	197	87.17
0152	Maximum Product Subarray	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(N)_Space_O(1)	253	88.42
0198	House Robber	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(n)_Space_O(n)	156	92.24
0213	House Robber II	Medium	Array, Dynamic_Programming	257	59.62
0509	Fibonacci Number	Easy	Dynamic_Programming, Math, Recursion, Memoization	139	82.72
0070	Climbing Stairs	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Math, Memoization, Big_O_Time_O(n)_Space_O(n)	124	71.98
0064	Minimum Path Sum	Medium	Top_100_Liked_Questions, Array, Dynamic_Programming, Matrix, Big_O_Time_O(m*n)_Space_O(m*n)	164	100.00
0300	Longest Increasing Subsequence	Medium	Top_100_Liked_Questions, Array, Dynamic_Programming, Binary_Search, Big_O_Time_O(n*log_n)_Space_O(n)	318	82.28
1143	Longest Common Subsequence	Medium	Top_100_Liked_Questions, String, Dynamic_Programming, Big_O_Time_O(n*m)_Space_O(n*m)	307	38.36
0072	Edit Distance	Medium	Top_100_Liked_Questions, String, Dynamic_Programming, Big_O_Time_O(n^2)_Space_O(n2)	182	92.16
0044	Wildcard Matching	Hard	Top_Interview_Questions, String, Dynamic_Programming, Greedy, Recursion	220	84.85
0010	Regular Expression Matching	Hard	Top_Interview_Questions, String, Dynamic_Programming, Recursion, Big_O_Time_O(m*n)_Space_O(m*n)	171	85.26

Udemy Backtracking/Recursion

0022	Generate Parentheses	Medium	Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Backtracking, Big_O_Time_O(2^n)_Space_O(n)	161	85.45
0039	Combination Sum	Medium	Top_100_Liked_Questions, Array, Backtracking, Big_O_Time_O(2^n)_Space_O(n+2^n)	226	88.89
0216	Combination Sum III	Medium	Array, Backtracking	175	90.91
0078	Subsets	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Bit_Manipulation, Backtracking, Big_O_Time_O(2^n)_Space_O(n*2^n)	171	94.92
0017	Letter Combinations of a Phone Number	Medium	Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Backtracking, Big_O_Time_O(4^n)_Space_O(n)	155	95.24
0046	Permutations	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Backtracking, Big_O_Time_O(n*n!)_Space_O(n+n!)	188	99.00

Udemy Bit Manipulation

0191	Number of 1 Bits	Easy	Top_Interview_Questions, Bit_Manipulation	237	68.44
0389	Find the Difference	Easy	String, Hash_Table, Sorting, Bit_Manipulation	256	64.81
0190	Reverse Bits	Easy	Top_Interview_Questions, Bit_Manipulation, Divide_and_Conquer	198	81.82
0461	Hamming Distance	Easy	Bit_Manipulation	150	96.15
1009	Complement of Base 10 Integer	Easy	Bit_Manipulation	126	72.73
0338	Counting Bits	Easy	Dynamic_Programming, Bit_Manipulation, Big_O_Time_O(num)_Space_O(num)	186	99.26
0371	Sum of Two Integers	Medium	Math, Bit_Manipulation	129	95.45
0029	Divide Two Integers	Medium	Top_Interview_Questions, Math, Bit_Manipulation	144	82.50

Udemy Design

0155	Min Stack	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Stack, Design, Big_O_Time_O(1)_Space_O(N)	331	84.88

Data Structure I

Day 1 Array

0217	Contains Duplicate	Easy	Top_Interview_Questions, Array, Hash_Table, Sorting	719	73.49
0053	Maximum Subarray	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Divide_and_Conquer, Big_O_Time_O(n)_Space_O(1)	510	78.81

Day 2 Array

0001	Two Sum	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Big_O_Time_O(n)_Space_O(n)	202	91.18
0088	Merge Sorted Array	Easy	Top_Interview_Questions, Array, Sorting, Two_Pointers	170	69.74

Day 3 Array

0350	Intersection of Two Arrays II	Easy	Array, Hash_Table, Sorting, Binary_Search, Two_Pointers	321	73.37
0121	Best Time to Buy and Sell Stock	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(N)_Space_O(1)	609	94.06

Day 4 Array

0566	Reshape the Matrix	Easy	Array, Matrix, Simulation	239	99.05
0118	Pascal's Triangle	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming	277	33.22

Day 5 Array

0036	Valid Sudoku	Medium	Top_Interview_Questions, Array, Hash_Table, Matrix	181	95.15
0074	Search a 2D Matrix	Medium	Top_100_Liked_Questions, Array, Binary_Search, Matrix, Big_O_Time_O(endRow+endCol)_Space_O(1)	159	74.46

Day 6 String

0387	First Unique Character in a String	Easy	String, Hash_Table, Counting, Queue	369	82.68
0383	Ransom Note	Easy	String, Hash_Table, Counting	333	79.58
0242	Valid Anagram	Easy	String, Hash_Table, Sorting	251	87.65

Day 7 Linked List

0141	Linked List Cycle	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Hash_Table, Two_Pointers, Linked_List, Big_O_Time_O(N)_Space_O(1)	223	91.85
0021	Merge Two Sorted Lists	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Linked_List, Recursion, Big_O_Time_O(m+n)_Space_O(m+n)	157	92.24
0203	Remove Linked List Elements	Easy	Linked_List, Recursion	233	91.22

Day 8 Linked List

0206	Reverse Linked List	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Linked_List, Recursion, Big_O_Time_O(N)_Space_O(1)	279	45.78
0083	Remove Duplicates from Sorted List	Easy	Linked_List	173	82.42

Day 9 Stack Queue

0020	Valid Parentheses	Easy	Top_100_Liked_Questions, Top_Interview_Questions, String, Stack, Big_O_Time_O(n)_Space_O(n)	137	88.76
0232	Implement Queue using Stacks	Easy	Stack, Design, Queue	258	70.86

Day 10 Tree

0144	Binary Tree Preorder Traversal	Easy	Depth_First_Search, Tree, Binary_Tree, Stack	277	37.90
0094	Binary Tree Inorder Traversal	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Tree, Binary_Tree, Stack, Big_O_Time_O(n)_Space_O(n)	152	66.67
0145	Binary Tree Postorder Traversal	Easy	Depth_First_Search, Tree, Binary_Tree, Stack	211	80.00

Day 11 Tree

0102	Binary Tree Level Order Traversal	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(N)_Space_O(N)	198	95.14
0104	Maximum Depth of Binary Tree	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(N)_Space_O(H)	166	83.53
0101	Symmetric Tree	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(N)_Space_O(log(N))	153	82.35

Day 12 Tree

0226	Invert Binary Tree	Easy	Top_100_Liked_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(n)_Space_O(n)	233	54.90
0112	Path Sum	Easy	Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree	322	36.41

Day 13 Tree

0700	Search in a Binary Search Tree	Easy	Tree, Binary_Tree, Binary_Search_Tree	251	88.31
0701	Insert into a Binary Search Tree	Medium	Tree, Binary_Tree, Binary_Search_Tree	311	79.03

Day 14 Tree

0098	Validate Binary Search Tree	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree, Big_O_Time_O(N)_Space_O(log(N))	190	61.62
0653	Two Sum IV - Input is a BST	Easy	Hash_Table, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Two_Pointers, Binary_Search_Tree	231	96.08
0235	Lowest Common Ancestor of a Binary Search Tree	Medium	Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree	404	75.59

Data Structure II

Day 1 Array

0136	Single Number	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Array, Bit_Manipulation, Big_O_Time_O(N)_Space_O(1)	344	83.63
0169	Majority Element	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Sorting, Counting, Divide_and_Conquer, Big_O_Time_O(n)_Space_O(1)	460	51.25
0015	3Sum	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Two_Pointers, Big_O_Time_O(n*log(n))_Space_O(n^2)	493	93.45

Day 2 Array

0075	Sort Colors	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Two_Pointers, Big_O_Time_O(n)_Space_O(1)	164	64.43
0056	Merge Intervals	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Big_O_Time_O(n_log_n)_Space_O(n)	334	80.67
0706	Design HashMap	Easy	Array, Hash_Table, Design, Linked_List, Hash_Function	405	92.11

Day 3 Array

0119	Pascal's Triangle II	Easy	Array, Dynamic_Programming	157	97.27
0048	Rotate Image	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Math, Matrix, Big_O_Time_O(n^2)_Space_O(1)	160	90.11
0059	Spiral Matrix II	Medium	Array, Matrix, Simulation	153	41.70

Day 4 Array

0240	Search a 2D Matrix II	Medium	Top_100_Liked_Questions, Array, Binary_Search, Matrix, Divide_and_Conquer, Big_O_Time_O(n+m)_Space_O(1)	460	66.08
0435	Non-overlapping Intervals	Medium	Array, Dynamic_Programming, Sorting, Greedy	1040	85.07

Day 5 Array

0334	Increasing Triplet Subsequence	Medium	Array, Greedy	672	60.61
0238	Product of Array Except Self	Medium	Top_100_Liked_Questions, Array, Prefix_Sum, Big_O_Time_O(n^2)_Space_O(n)	669	48.96
0560	Subarray Sum Equals K	Medium	Top_100_Liked_Questions, Array, Hash_Table, Prefix_Sum, Big_O_Time_O(n)_Space_O(n)	692	53.27

Day 6 String

0415	Add Strings	Easy	String, Math, Simulation	296	76.00
0409	Longest Palindrome	Easy	String, Hash_Table, Greedy	259	60.71

Day 7 String

0290	Word Pattern	Easy	String, Hash_Table	177	89.55
0763	Partition Labels	Medium	String, Hash_Table, Greedy, Two_Pointers, Big_O_Time_O(n)_Space_O(1)	235	84.75

Day 8 String

0049	Group Anagrams	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, String, Hash_Table, Sorting, Big_O_Time_O(n*k_log_k)_Space_O(n)	308	96.34
0043	Multiply Strings	Medium	String, Math, Simulation	165	96.72

Day 9 String

0187	Repeated DNA Sequences	Medium	String, Hash_Table, Bit_Manipulation, Sliding_Window, Hash_Function, Rolling_Hash	319	79.03
0005	Longest Palindromic Substring	Medium	Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Big_O_Time_O(n)_Space_O(n)	162	99.00

Day 10 Linked List

0002	Add Two Numbers	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Math, Linked_List, Recursion, Big_O_Time_O(max(N,M))_Space_O(max(N,M))	203	96.13
0142	Linked List Cycle II	Medium	Top_100_Liked_Questions, Hash_Table, Two_Pointers, Linked_List, Big_O_Time_O(N)_Space_O(1)	192	63.39

Day 11 Linked List

0160	Intersection of Two Linked Lists	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Hash_Table, Two_Pointers, Linked_List, Big_O_Time_O(M+N)_Space_O(1)	262	83.50
0082	Remove Duplicates from Sorted List II	Medium	Two_Pointers, Linked_List	166	89.47

Day 12 Linked List

0024	Swap Nodes in Pairs	Medium	Top_100_Liked_Questions, Linked_List, Recursion, Big_O_Time_O(n)_Space_O(1)	149	44.20
0707	Design Linked List	Medium	Design, Linked_List	243	100.00

Day 13 Linked List

0025	Reverse Nodes in k-Group	Hard	Top_100_Liked_Questions, Linked_List, Recursion, Big_O_Time_O(n)_Space_O(k)	189	67.03
0143	Reorder List	Medium	Two_Pointers, Stack, Linked_List, Recursion	395	82.26

Day 14 Stack Queue

0155	Min Stack	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Stack, Design, Big_O_Time_O(1)_Space_O(N)	331	84.88
1249	Minimum Remove to Make Valid Parentheses	Medium	String, Stack	218	100.00
1823	Find the Winner of the Circular Game	Medium	Array, Math, Simulation, Recursion, Queue	119	87.50

Day 15 Tree

0108	Convert Sorted Array to Binary Search Tree	Easy	Top_Interview_Questions, Array, Tree, Binary_Tree, Binary_Search_Tree, Divide_and_Conquer	167	80.29
0105	Construct Binary Tree from Preorder and Inorder Traversal	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Tree, Binary_Tree, Divide_and_Conquer, Big_O_Time_O(N)_Space_O(N)	183	95.45
0103	Binary Tree Zigzag Level Order Traversal	Medium	Top_Interview_Questions, Breadth_First_Search, Tree, Binary_Tree	176	71.62

Day 16 Tree

0199	Binary Tree Right Side View	Medium	Top_100_Liked_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree	194	92.89
0113	Path Sum II	Medium	Depth_First_Search, Tree, Binary_Tree, Backtracking	364	78.67
0450	Delete Node in a BST	Medium	Tree, Binary_Tree, Binary_Search_Tree	257	84.62

Day 17 Tree

0230	Kth Smallest Element in a BST	Medium	Top_100_Liked_Questions, Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree, Big_O_Time_O(n)_Space_O(n)	393	33.33
0173	Binary Search Tree Iterator	Medium	Tree, Binary_Tree, Stack, Design, Binary_Search_Tree, Iterator	563	46.91

Day 18 Tree

0236	Lowest Common Ancestor of a Binary Tree	Medium	Top_100_Liked_Questions, Depth_First_Search, Tree, Binary_Tree, Big_O_Time_O(n)_Space_O(n)	386	45.21
0297	Serialize and Deserialize Binary Tree	Hard	String, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Design	475	78.85

Day 19 Graph

0997	Find the Town Judge	Easy	Array, Hash_Table, Graph	475	58.62
1557	Minimum Number of Vertices to Reach All Nodes	Medium	Graph	792	99.29
0841	Keys and Rooms	Medium	Depth_First_Search, Breadth_First_Search, Graph	189	69.23

Day 20 Heap Priority Queue

0215	Kth Largest Element in an Array	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Heap_Priority_Queue, Divide_and_Conquer, Quickselect, Big_O_Time_O(n*log(n))_Space_O(log(n))	839	34.43
0347	Top K Frequent Elements	Medium	Top_100_Liked_Questions, Array, Hash_Table, Sorting, Heap_Priority_Queue, Counting, Divide_and_Conquer, Quickselect, Bucket_Sort, Big_O_Time_O(n*log(n))_Space_O(k)	268	99.74

Day 21 Heap Priority Queue

0451	Sort Characters By Frequency	Medium	String, Hash_Table, Sorting, Heap_Priority_Queue, Counting, Bucket_Sort	288	81.72
0973	K Closest Points to Origin	Medium	Array, Math, Sorting, Heap_Priority_Queue, Divide_and_Conquer, Geometry, Quickselect	800	37.89

Algorithm I

Day 1 Binary Search

0704	Binary Search	Easy	Top_100_Liked_Questions, Array, Binary_Search	261	77.91
0278	First Bad Version	Easy	Binary_Search, Interactive	349	76.86
0035	Search Insert Position	Easy	Top_100_Liked_Questions, Array, Binary_Search, Big_O_Time_O(log_n)_Space_O(1)	159	93.03

Day 2 Two Pointers

0977	Squares of a Sorted Array	Easy	Array, Sorting, Two_Pointers	271	77.17
0189	Rotate Array	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Math, Two_Pointers, Big_O_Time_O(n)_Space_O(1)	483	86.95

Day 3 Two Pointers

0283	Move Zeroes	Easy	Top_100_Liked_Questions, Array, Two_Pointers, Big_O_Time_O(n)_Space_O(1)	516	79.07
0167	Two Sum II - Input Array Is Sorted	Medium	Array, Binary_Search, Two_Pointers	403	68.74

Day 4 Two Pointers

0344	Reverse String	Easy	String, Two_Pointers, Recursion	445	69.75
0557	Reverse Words in a String III	Easy	String, Two_Pointers	215	98.10

Day 5 Two Pointers

0876	Middle of the Linked List	Easy	Two_Pointers, Linked_List	136	76.52
0019	Remove Nth Node From End of List	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Two_Pointers, Linked_List, Big_O_Time_O(L)_Space_O(L)	144	96.28

Day 6 Sliding Window

0003	Longest Substring Without Repeating Characters	Medium	Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Sliding_Window, Big_O_Time_O(n)_Space_O(1)	201	87.28
0567	Permutation in String	Medium	Top_100_Liked_Questions, String, Hash_Table, Two_Pointers, Sliding_Window	169	100.00

Day 7 Breadth First Search Depth First Search

0733	Flood Fill	Easy	Array, Depth_First_Search, Breadth_First_Search, Matrix	230	97.76
0695	Max Area of Island	Medium	Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find	324	24.06

Day 8 Breadth First Search Depth First Search

0617	Merge Two Binary Trees	Easy	Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree	243	72.83
0116	Populating Next Right Pointers in Each Node	Medium	Top_Interview_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Linked_List	355	69.02

Day 9 Breadth First Search Depth First Search

0542	01 Matrix	Medium	Array, Dynamic_Programming, Breadth_First_Search, Matrix	441	94.06
0994	Rotting Oranges	Medium	Top_100_Liked_Questions, Array, Breadth_First_Search, Matrix	164	82.95

Day 10 Recursion Backtracking

0021	Merge Two Sorted Lists	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Linked_List, Recursion, Big_O_Time_O(m+n)_Space_O(m+n)	157	92.24
0206	Reverse Linked List	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Linked_List, Recursion, Big_O_Time_O(N)_Space_O(1)	279	45.78

Day 11 Recursion Backtracking

0077	Combinations	Medium	Backtracking	232	100.00
0046	Permutations	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Backtracking, Big_O_Time_O(n*n!)_Space_O(n+n!)	188	99.00
0784	Letter Case Permutation	Medium	String, Bit_Manipulation, Backtracking	219	84.62

Day 12 Dynamic Programming

0070	Climbing Stairs	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Math, Memoization, Big_O_Time_O(n)_Space_O(n)	124	71.98
0198	House Robber	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(n)_Space_O(n)	156	92.24
0120	Triangle	Medium	Array, Dynamic_Programming	194	97.87

Day 13 Bit Manipulation

0231	Power of Two	Easy	Math, Bit_Manipulation, Recursion	161	86.81
0191	Number of 1 Bits	Easy	Top_Interview_Questions, Bit_Manipulation	237	68.44

Day 14 Bit Manipulation

0190	Reverse Bits	Easy	Top_Interview_Questions, Bit_Manipulation, Divide_and_Conquer	198	81.82
0136	Single Number	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Array, Bit_Manipulation, Big_O_Time_O(N)_Space_O(1)	344	83.63

Algorithm II

Day 1 Binary Search

0034	Find First and Last Position of Element in Sorted Array	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Binary_Search, Big_O_Time_O(log_n)_Space_O(1)	174	100.00
0033	Search in Rotated Sorted Array	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Binary_Search, Big_O_Time_O(log_n)_Space_O(1)	151	93.77
0074	Search a 2D Matrix	Medium	Top_100_Liked_Questions, Array, Binary_Search, Matrix, Big_O_Time_O(endRow+endCol)_Space_O(1)	159	74.46

Day 2 Binary Search

0153	Find Minimum in Rotated Sorted Array	Medium	Top_100_Liked_Questions, Array, Binary_Search, Big_O_Time_O(log_N)_Space_O(log_N)	262	60.96
0162	Find Peak Element	Medium	Top_Interview_Questions, Array, Binary_Search	297	53.85

Day 3 Two Pointers

0082	Remove Duplicates from Sorted List II	Medium	Two_Pointers, Linked_List	166	89.47
0015	3Sum	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Two_Pointers, Big_O_Time_O(n*log(n))_Space_O(n^2)	493	93.45

Day 4 Two Pointers

0844	Backspace String Compare	Easy	String, Two_Pointers, Stack, Simulation	126	98.31
0986	Interval List Intersections	Medium	Array, Two_Pointers	318	60.98
0011	Container With Most Water	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Greedy, Two_Pointers, Big_O_Time_O(n)_Space_O(1)	402	78.57

Day 5 Sliding Window

0438	Find All Anagrams in a String	Medium	Top_100_Liked_Questions, String, Hash_Table, Sliding_Window, Big_O_Time_O(n+m)_Space_O(1)	561	54.68
0713	Subarray Product Less Than K	Medium	Array, Sliding_Window	336	92.11
0209	Minimum Size Subarray Sum	Medium	Array, Binary_Search, Prefix_Sum, Sliding_Window	315	96.73

Day 6 Breadth First Search Depth First Search

0200	Number of Islands	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find, Big_O_Time_O(M*N)_Space_O(M*N)	252	95.41
0547	Number of Provinces	Medium	Depth_First_Search, Breadth_First_Search, Graph, Union_Find	229	79.73

Day 7 Breadth First Search Depth First Search

0117	Populating Next Right Pointers in Each Node II	Medium	Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Linked_List	199	94.67
0572	Subtree of Another Tree	Easy	Depth_First_Search, Tree, Binary_Tree, Hash_Function, String_Matching	214	92.39

Day 8 Breadth First Search Depth First Search

1091	Shortest Path in Binary Matrix	Medium	Array, Breadth_First_Search, Matrix	305	98.28
0130	Surrounded Regions	Medium	Top_Interview_Questions, Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find	355	84.42
0797	All Paths From Source to Target	Medium	Depth_First_Search, Breadth_First_Search, Graph, Backtracking	232	100.00

Day 9 Recursion Backtracking

0078	Subsets	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Bit_Manipulation, Backtracking, Big_O_Time_O(2^n)_Space_O(n*2^n)	171	94.92
0090	Subsets II	Medium	Array, Bit_Manipulation, Backtracking	200	88.33

Day 10 Recursion Backtracking

0047	Permutations II	Medium	Array, Backtracking	199	100.00
0039	Combination Sum	Medium	Top_100_Liked_Questions, Array, Backtracking, Big_O_Time_O(2^n)_Space_O(n+2^n)	226	88.89
0040	Combination Sum II	Medium	Array, Backtracking	217	93.75

Day 11 Recursion Backtracking

0017	Letter Combinations of a Phone Number	Medium	Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Backtracking, Big_O_Time_O(4^n)_Space_O(n)	155	95.24
0022	Generate Parentheses	Medium	Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Backtracking, Big_O_Time_O(2^n)_Space_O(n)	161	85.45
0079	Word Search	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Matrix, Backtracking, Big_O_Time_O(4^(m*n))_Space_O(m*n)	392	72.92

Day 12 Dynamic Programming

0213	House Robber II	Medium	Array, Dynamic_Programming	257	59.62
0055	Jump Game	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Greedy, Big_O_Time_O(n)_Space_O(1)	332	89.35

Day 13 Dynamic Programming

0045	Jump Game II	Medium	Top_100_Liked_Questions, Array, Dynamic_Programming, Greedy, Big_O_Time_O(n)_Space_O(1)	208	93.37
0062	Unique Paths	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Math, Combinatorics, Big_O_Time_O(m*n)_Space_O(m*n)	118	94.65

Day 14 Dynamic Programming

0005	Longest Palindromic Substring	Medium	Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Big_O_Time_O(n)_Space_O(n)	162	99.00
0413	Arithmetic Slices	Medium	Array, Dynamic_Programming	156	100.00

Day 15 Dynamic Programming

0091	Decode Ways	Medium	Top_Interview_Questions, String, Dynamic_Programming	148	79.07
0139	Word Break	Medium	Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Dynamic_Programming, Trie, Memoization, Big_O_Time_O(M+max*N)_Space_O(M+N+max)	197	87.17

Day 16 Dynamic Programming

0300	Longest Increasing Subsequence	Medium	Top_100_Liked_Questions, Array, Dynamic_Programming, Binary_Search, Big_O_Time_O(n*log_n)_Space_O(n)	318	82.28
0673	Number of Longest Increasing Subsequence	Medium	Array, Dynamic_Programming, Segment_Tree, Binary_Indexed_Tree	226	91.67

Day 17 Dynamic Programming

1143	Longest Common Subsequence	Medium	Top_100_Liked_Questions, String, Dynamic_Programming, Big_O_Time_O(n*m)_Space_O(n*m)	307	38.36
0583	Delete Operation for Two Strings	Medium	String, Dynamic_Programming	197	100.00

Day 18 Dynamic Programming

0072	Edit Distance	Medium	Top_100_Liked_Questions, String, Dynamic_Programming, Big_O_Time_O(n^2)_Space_O(n2)	182	92.16
0322	Coin Change	Medium	Top_100_Liked_Questions, Array, Dynamic_Programming, Breadth_First_Search, Big_O_Time_O(m*n)_Space_O(amount)	332	50.68
0343	Integer Break	Medium	Dynamic_Programming, Math	218	63.89

Day 19 Bit Manipulation

0201	Bitwise AND of Numbers Range	Medium	Bit_Manipulation	368	80.00

Day 20 Others

0384	Shuffle an Array	Medium	Array, Math, Randomized	940	72.09

Day 21 Others

0202	Happy Number	Easy	Top_Interview_Questions, Hash_Table, Math, Two_Pointers	261	45.08
0149	Max Points on a Line	Hard	Top_Interview_Questions, Array, Hash_Table, Math, Geometry	307	83.33

Binary Search I

Day 1

0704	Binary Search	Easy	Top_100_Liked_Questions, Array, Binary_Search	261	77.91
0374	Guess Number Higher or Lower	Easy	Binary_Search, Interactive	134	94.19

Day 2

0035	Search Insert Position	Easy	Top_100_Liked_Questions, Array, Binary_Search, Big_O_Time_O(log_n)_Space_O(1)	159	93.03
0852	Peak Index in a Mountain Array	Medium	Array, Binary_Search	433	94.29

Day 3

0367	Valid Perfect Square	Easy	Math, Binary_Search	137	94.55
1385	Find the Distance Value Between Two Arrays	Easy	Array, Sorting, Binary_Search, Two_Pointers	190	84.62

Day 4

0069	Sqrt(x)	Easy	Top_Interview_Questions, Math, Binary_Search	140	94.72
0744	Find Smallest Letter Greater Than Target	Easy	Array, Binary_Search	162	100.00

Day 5

0278	First Bad Version	Easy	Binary_Search, Interactive	349	76.86
0034	Find First and Last Position of Element in Sorted Array	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Binary_Search, Big_O_Time_O(log_n)_Space_O(1)	174	100.00

Day 6

0441	Arranging Coins	Easy	Math, Binary_Search	150	84.21
1539	Kth Missing Positive Number	Easy	Array, Binary_Search	153	100.00

Day 7

0167	Two Sum II - Input Array Is Sorted	Medium	Array, Binary_Search, Two_Pointers	403	68.74
1608	Special Array With X Elements Greater Than or Equal X	Easy	Array, Sorting, Binary_Search	147	81.82

Day 8

1351	Count Negative Numbers in a Sorted Matrix	Easy	Array, Binary_Search, Matrix	206	71.43
0074	Search a 2D Matrix	Medium	Top_100_Liked_Questions, Array, Binary_Search, Matrix, Big_O_Time_O(endRow+endCol)_Space_O(1)	159	74.46

Day 9

1337	The K Weakest Rows in a Matrix	Easy	Array, Sorting, Binary_Search, Matrix, Heap_Priority_Queue	216	77.59
1346	Check If N and Its Double Exist	Easy	Array, Hash_Table, Sorting, Binary_Search, Two_Pointers	175	70.83

Day 10

0350	Intersection of Two Arrays II	Easy	Array, Hash_Table, Sorting, Binary_Search, Two_Pointers	321	73.37
0633	Sum of Square Numbers	Medium	Math, Binary_Search, Two_Pointers	126	100.00

Day 11

1855	Maximum Distance Between a Pair of Values	Medium	Array, Greedy, Binary_Search, Two_Pointers	458	100.00
0033	Search in Rotated Sorted Array	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Binary_Search, Big_O_Time_O(log_n)_Space_O(1)	151	93.77

Day 12

0153	Find Minimum in Rotated Sorted Array	Medium	Top_100_Liked_Questions, Array, Binary_Search, Big_O_Time_O(log_N)_Space_O(log_N)	262	60.96

Binary Search II

Day 1

0209	Minimum Size Subarray Sum	Medium	Array, Binary_Search, Prefix_Sum, Sliding_Window	315	96.73
0611	Valid Triangle Number	Medium	Array, Sorting, Greedy, Binary_Search, Two_Pointers	203	100.00

Day 2

0658	Find K Closest Elements	Medium	Array, Sorting, Binary_Search, Two_Pointers, Heap_Priority_Queue	375	95.16
1894	Find the Student that Will Replace the Chalk	Medium	Array, Binary_Search, Simulation, Prefix_Sum	520	50.00

Day 3

0300	Longest Increasing Subsequence	Medium	Top_100_Liked_Questions, Array, Dynamic_Programming, Binary_Search, Big_O_Time_O(n*log_n)_Space_O(n)	318	82.28
1760	Minimum Limit of Balls in a Bag	Medium	Array, Binary_Search	460	100.00

Day 4

0875	Koko Eating Bananas	Medium	Array, Binary_Search	267	93.85
1552	Magnetic Force Between Two Balls	Medium	Array, Sorting, Binary_Search	636	100.00

Day 5

0287	Find the Duplicate Number	Medium	Top_100_Liked_Questions, Array, Binary_Search, Two_Pointers, Bit_Manipulation, Big_O_Time_O(n)_Space_O(n)	656	66.21
1283	Find the Smallest Divisor Given a Threshold	Medium	Array, Binary_Search	255	100.00

Day 6

1898	Maximum Number of Removable Characters	Medium	Array, String, Binary_Search	636	100.00
1870	Minimum Speed to Arrive on Time	Medium	Array, Binary_Search	628	50.00

Day 7

1482	Minimum Number of Days to Make m Bouquets	Medium	Array, Binary_Search	538	50.00
1818	Minimum Absolute Sum Difference	Medium	Array, Sorting, Binary_Search, Ordered_Set	447	100.00

Day 8

0240	Search a 2D Matrix II	Medium	Top_100_Liked_Questions, Array, Binary_Search, Matrix, Divide_and_Conquer, Big_O_Time_O(n+m)_Space_O(1)	460	66.08
0275	H-Index II	Medium	Array, Binary_Search	398	81.82

Day 9

1838	Frequency of the Most Frequent Element	Medium	Array, Sorting, Greedy, Binary_Search, Prefix_Sum, Sliding_Window	564	88.89
0540	Single Element in a Sorted Array	Medium	Array, Binary_Search	274	86.67

Day 10

0222	Count Complete Tree Nodes
1712	Ways to Split Array Into Three Subarrays	Medium	Array, Binary_Search, Two_Pointers, Prefix_Sum	486	100.00

Day 11

0826	Most Profit Assigning Work	Medium	Array, Sorting, Greedy, Binary_Search, Two_Pointers	366	100.00
0436	Find Right Interval	Medium	Array, Sorting, Binary_Search	333	100.00

Day 12

0081	Search in Rotated Sorted Array II	Medium	Array, Binary_Search	170	96.30
0162	Find Peak Element	Medium	Top_Interview_Questions, Array, Binary_Search	297	53.85

Day 13

0154	Find Minimum in Rotated Sorted Array II	Hard	Array, Binary_Search	275	84.00
0528	Random Pick with Weight	Medium	Math, Binary_Search, Prefix_Sum, Randomized	393	91.38

Day 14

1508	Range Sum of Sorted Subarray Sums	Medium	Array, Sorting, Binary_Search, Two_Pointers	378	66.67
1574	Shortest Subarray to be Removed to Make Array Sorted	Medium	Array, Binary_Search, Two_Pointers, Stack, Monotonic_Stack	477	50.00

Day 15

1292	Maximum Side Length of a Square with Sum Less than or Equal to Threshold	Medium	Array, Binary_Search, Matrix, Prefix_Sum	376	100.00
1498	Number of Subsequences That Satisfy the Given Sum Condition	Medium	Array, Sorting, Binary_Search, Two_Pointers	487	97.89

Day 16

0981	Time Based Key-Value Store	Medium	String, Hash_Table, Binary_Search, Design	1011	65.56
1300	Sum of Mutated Array Closest to Target	Medium	Array, Sorting, Binary_Search	217	100.00

Day 17

1802	Maximum Value at a Given Index in a Bounded Array	Medium	Greedy, Binary_Search	118	100.00
1901	Find a Peak Element II	Medium	Array, Binary_Search, Matrix, Divide_and_Conquer	726	100.00

Day 18

1146	Snapshot Array	Medium	Array, Hash_Table, Binary_Search, Design	1064	57.14
1488	Avoid Flood in The City	Medium	Array, Hash_Table, Greedy, Binary_Search, Heap_Priority_Queue	823	66.67

Day 19

1562	Find Latest Group of Size M	Medium	Array, Binary_Search, Simulation	534	100.00
1648	Sell Diminishing-Valued Colored Balls	Medium	Array, Math, Sorting, Greedy, Binary_Search, Heap_Priority_Queue	509	100.00

Day 20

1201	Ugly Number III	Medium	Math, Binary_Search, Number_Theory	136	100.00
0911	Online Election	Medium	Array, Hash_Table, Binary_Search, Design	766	83.33

Dynamic Programming I

Day 1

0509	Fibonacci Number	Easy	Dynamic_Programming, Math, Recursion, Memoization	139	82.72
1137	N-th Tribonacci Number	Easy	Dynamic_Programming, Math, Memoization	122	69.35

Day 2

0070	Climbing Stairs	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Math, Memoization, Big_O_Time_O(n)_Space_O(n)	124	71.98
0746	Min Cost Climbing Stairs	Easy	Array, Dynamic_Programming	171	96.76

Day 3

0198	House Robber	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(n)_Space_O(n)	156	92.24
0213	House Robber II	Medium	Array, Dynamic_Programming	257	59.62
0740	Delete and Earn	Medium	Array, Hash_Table, Dynamic_Programming	192	100.00

Day 4

0055	Jump Game	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Greedy, Big_O_Time_O(n)_Space_O(1)	332	89.35
0045	Jump Game II	Medium	Top_100_Liked_Questions, Array, Dynamic_Programming, Greedy, Big_O_Time_O(n)_Space_O(1)	208	93.37

Day 5

0053	Maximum Subarray	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Divide_and_Conquer, Big_O_Time_O(n)_Space_O(1)	510	78.81
0918	Maximum Sum Circular Subarray	Medium	Array, Dynamic_Programming, Divide_and_Conquer, Queue, Monotonic_Queue	339	86.96

Day 6

0152	Maximum Product Subarray	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(N)_Space_O(1)	253	88.42
1567	Maximum Length of Subarray With Positive Product	Medium	Array, Dynamic_Programming, Greedy	468	33.33

Day 7

1014	Best Sightseeing Pair	Medium	Array, Dynamic_Programming	336	66.67
0121	Best Time to Buy and Sell Stock	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(N)_Space_O(1)	609	94.06
0122	Best Time to Buy and Sell Stock II	Medium	Top_Interview_Questions, Array, Dynamic_Programming, Greedy	197	95.10

Day 8

0309	Best Time to Buy and Sell Stock with Cooldown	Medium	Array, Dynamic_Programming	272	73.33
0714	Best Time to Buy and Sell Stock with Transaction Fee	Medium	Array, Dynamic_Programming, Greedy	417	90.91

Day 9

0139	Word Break	Medium	Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Dynamic_Programming, Trie, Memoization, Big_O_Time_O(M+max*N)_Space_O(M+N+max)	197	87.17
0042	Trapping Rain Water	Hard	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Two_Pointers, Stack, Monotonic_Stack, Big_O_Time_O(n)_Space_O(1)	189	99.37

Day 10

0413	Arithmetic Slices	Medium	Array, Dynamic_Programming	156	100.00
0091	Decode Ways	Medium	Top_Interview_Questions, String, Dynamic_Programming	148	79.07

Day 11

0264	Ugly Number II	Medium	Hash_Table, Dynamic_Programming, Math, Heap_Priority_Queue	182	95.45
0096	Unique Binary Search Trees	Medium	Dynamic_Programming, Math, Tree, Binary_Tree, Binary_Search_Tree, Big_O_Time_O(n)_Space_O(1)	116	92.31

Day 12

0118	Pascal's Triangle	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming	277	33.22
0119	Pascal's Triangle II	Easy	Array, Dynamic_Programming	157	97.27

Day 13

0931	Minimum Falling Path Sum	Medium	Array, Dynamic_Programming, Matrix	201	84.21
0120	Triangle	Medium	Array, Dynamic_Programming	194	97.87

Day 14

1314	Matrix Block Sum	Medium	Array, Matrix, Prefix_Sum	235	100.00
0304	Range Sum Query 2D - Immutable	Medium	Array, Matrix, Design, Prefix_Sum	1373	85.71

Day 15

0062	Unique Paths	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Math, Combinatorics, Big_O_Time_O(m*n)_Space_O(m*n)	118	94.65
0063	Unique Paths II	Medium	Array, Dynamic_Programming, Matrix	151	81.94

Day 16

0064	Minimum Path Sum	Medium	Top_100_Liked_Questions, Array, Dynamic_Programming, Matrix, Big_O_Time_O(m*n)_Space_O(m*n)	164	100.00
0221	Maximal Square	Medium	Array, Dynamic_Programming, Matrix, Big_O_Time_O(m*n)_Space_O(m*n)	614	44.00

Day 17

0005	Longest Palindromic Substring	Medium	Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Big_O_Time_O(n)_Space_O(n)	162	99.00
0516	Longest Palindromic Subsequence	Medium	String, Dynamic_Programming	243	87.50

Day 18

0300	Longest Increasing Subsequence	Medium	Top_100_Liked_Questions, Array, Dynamic_Programming, Binary_Search, Big_O_Time_O(n*log_n)_Space_O(n)	318	82.28
0376	Wiggle Subsequence	Medium	Array, Dynamic_Programming, Greedy	162	88.89

Day 19

0392	Is Subsequence	Easy	String, Dynamic_Programming, Two_Pointers	156	87.74
1143	Longest Common Subsequence	Medium	Top_100_Liked_Questions, String, Dynamic_Programming, Big_O_Time_O(n*m)_Space_O(n*m)	307	38.36
0072	Edit Distance	Medium	Top_100_Liked_Questions, String, Dynamic_Programming, Big_O_Time_O(n^2)_Space_O(n2)	182	92.16

Day 20

0322	Coin Change	Medium	Top_100_Liked_Questions, Array, Dynamic_Programming, Breadth_First_Search, Big_O_Time_O(m*n)_Space_O(amount)	332	50.68
0518	Coin Change II	Medium	Array, Dynamic_Programming	139	100.00

Day 21

0377	Combination Sum IV	Medium	Array, Dynamic_Programming	217	72.41
0343	Integer Break	Medium	Dynamic_Programming, Math	218	63.89
0279	Perfect Squares	Medium	Dynamic_Programming, Math, Breadth_First_Search	176	98.80

Programming Skills I

Day 1 Basic Data Type

1523	Count Odd Numbers in an Interval Range	Easy	Math	114	97.22
1491	Average Salary Excluding the Minimum and Maximum Salary	Easy	Array, Sorting	165	27.87

Day 2 Operator

0191	Number of 1 Bits	Easy	Top_Interview_Questions, Bit_Manipulation	237	68.44
1281	Subtract the Product and Sum of Digits of an Integer	Easy	Math	128	61.82

Day 3 Conditional Statements

0976	Largest Perimeter Triangle	Easy	Array, Math, Sorting, Greedy	304	33.33
1779	Find Nearest Point That Has the Same X or Y Coordinate	Easy	Array	364	100.00

Day 4 Loop

1822	Sign of the Product of an Array	Easy	Array, Math	170	92.51
1502	Can Make Arithmetic Progression From Sequence	Easy	Array, Sorting	156	94.82
0202	Happy Number	Easy	Top_Interview_Questions, Hash_Table, Math, Two_Pointers	261	45.08
1790	Check if One String Swap Can Make Strings Equal	Easy	String, Hash_Table, Counting	138	100.00

Day 5 Function

0589	N-ary Tree Preorder Traversal	Easy	Depth_First_Search, Tree, Stack	233	84.02
0496	Next Greater Element I	Easy	Array, Hash_Table, Stack, Monotonic_Stack	171	100.00
1232	Check If It Is a Straight Line	Easy	Array, Math, Geometry	152	95.38

Day 6 Array

1588	Sum of All Odd Length Subarrays	Easy	Array, Math, Prefix_Sum	157	64.00
0283	Move Zeroes	Easy	Top_100_Liked_Questions, Array, Two_Pointers, Big_O_Time_O(n)_Space_O(1)	516	79.07
1672	Richest Customer Wealth	Easy	Array, Matrix	155	94.54

Day 7 Array

1572	Matrix Diagonal Sum	Easy	Array, Matrix	221	67.61
0566	Reshape the Matrix	Easy	Array, Matrix, Simulation	239	99.05

Day 8 String

1768	Merge Strings Alternately	Easy	String, Two_Pointers	138	93.81
1678	Goal Parser Interpretation	Easy	String	136	88.24
0389	Find the Difference	Easy	String, Hash_Table, Sorting, Bit_Manipulation	256	64.81

Day 9 String

0709	To Lower Case	Easy	String	142	98.68
1309	Decrypt String from Alphabet to Integer Mapping	Easy	String	129	95.45
0953	Verifying an Alien Dictionary	Easy	Array, String, Hash_Table	137	100.00

Day 10 Linked List and Tree

1290	Convert Binary Number in a Linked List to Integer	Easy	Math, Linked_List	145	25.93
0876	Middle of the Linked List	Easy	Two_Pointers, Linked_List	136	76.52
0104	Maximum Depth of Binary Tree	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(N)_Space_O(H)	166	83.53
0404	Sum of Left Leaves	Easy	Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree	173	86.05

Day 11 Containers and Libraries

1356	Sort Integers by The Number of 1 Bits	Easy	Array, Sorting, Bit_Manipulation, Counting	236	92.31
0232	Implement Queue using Stacks	Easy	Stack, Design, Queue	258	70.86
0242	Valid Anagram	Easy	String, Hash_Table, Sorting	251	87.65
0217	Contains Duplicate	Easy	Top_Interview_Questions, Array, Hash_Table, Sorting	719	73.49

Day 12 Class and Object

1603	Design Parking System	Easy	Design, Simulation, Counting	376	31.83
0303	Range Sum Query - Immutable	Easy	Array, Design, Prefix_Sum	472	63.64

Programming Skills II

Day 1

0896	Monotonic Array	Easy	Array	576	90.91
0028	Find the Index of the First Occurrence in a String	Easy	Top_Interview_Questions, String, Two_Pointers, String_Matching	126	97.58

Day 2

0110	Balanced Binary Tree	Easy	Depth_First_Search, Tree, Binary_Tree	182	71.30
0459	Repeated Substring Pattern	Easy	String, String_Matching	201	100.00

Day 3

0150	Evaluate Reverse Polish Notation	Medium	Top_Interview_Questions, Array, Math, Stack	233	88.82
0066	Plus One	Easy	Top_Interview_Questions, Array, Math	148	98.75

Day 4

1367	Linked List in Binary Tree	Medium	Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Linked_List	237	92.86
0043	Multiply Strings	Medium	String, Math, Simulation	165	96.72

Day 5

0067	Add Binary	Easy	String, Math, Bit_Manipulation, Simulation	164	90.60
0989	Add to Array-Form of Integer	Easy	Array, Math	350	70.00

Day 6

0739	Daily Temperatures	Medium	Top_100_Liked_Questions, Array, Stack, Monotonic_Stack, Big_O_Time_O(n)_Space_O(n)	936	80.54
0058	Length of Last Word	Easy	String	135	93.67

Day 7

0048	Rotate Image	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Math, Matrix, Big_O_Time_O(n^2)_Space_O(1)	160	90.11
1886	Determine Whether Matrix Can Be Obtained By Rotation	Easy	Array, Matrix	147	85.71

Day 8

0054	Spiral Matrix	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Matrix, Simulation	132	95.12
0973	K Closest Points to Origin	Medium	Array, Math, Sorting, Heap_Priority_Queue, Divide_and_Conquer, Geometry, Quickselect	800	37.89

Day 9

1630	Arithmetic Subarrays	Medium	Array, Sorting	264	100.00
0429	N-ary Tree Level Order Traversal	Medium	Breadth_First_Search, Tree	248	75.86

Day 10

0503	Next Greater Element II	Medium	Array, Stack, Monotonic_Stack	331	92.68
0556	Next Greater Element III	Medium	String, Math, Two_Pointers	137	80.00

Day 11

1376	Time Needed to Inform All Employees	Medium	Depth_First_Search, Breadth_First_Search, Tree	915	37.62
0049	Group Anagrams	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, String, Hash_Table, Sorting, Big_O_Time_O(n*k_log_k)_Space_O(n)	308	96.34

Day 12

0438	Find All Anagrams in a String	Medium	Top_100_Liked_Questions, String, Hash_Table, Sliding_Window, Big_O_Time_O(n+m)_Space_O(1)	561	54.68
0713	Subarray Product Less Than K	Medium	Array, Sliding_Window	336	92.11

Day 13

0304	Range Sum Query 2D - Immutable	Medium	Array, Matrix, Design, Prefix_Sum	1373	85.71
0910	Smallest Range II	Medium	Array, Math, Sorting, Greedy	234	100.00

Day 14

0143	Reorder List	Medium	Two_Pointers, Stack, Linked_List, Recursion	395	82.26
0138	Copy List with Random Pointer	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Hash_Table, Linked_List, Big_O_Time_O(N)_Space_O(N)	274	80.58

Day 15

0002	Add Two Numbers	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Math, Linked_List, Recursion, Big_O_Time_O(max(N,M))_Space_O(max(N,M))	203	96.13
0445	Add Two Numbers II	Medium	Math, Stack, Linked_List	240	82.61

Day 16

0061	Rotate List	Medium	Two_Pointers, Linked_List	160	92.22
0173	Binary Search Tree Iterator	Medium	Tree, Binary_Tree, Stack, Design, Binary_Search_Tree, Iterator	563	46.91

Day 17

1845	Seat Reservation Manager	Medium	Design, Heap_Priority_Queue	834	100.00
0860	Lemonade Change	Easy	Array, Greedy	413	86.96

Day 18

0155	Min Stack	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Stack, Design, Big_O_Time_O(1)_Space_O(N)	331	84.88
0341	Flatten Nested List Iterator	Medium	Depth_First_Search, Tree, Stack, Design, Queue, Iterator	210	100.00

Day 19

1797	Design Authentication Manager	Medium	Hash_Table, Design	334	100.00
0707	Design Linked List	Medium	Design, Linked_List	243	100.00

Day 20

0380	Insert Delete GetRandom O(1)	Medium	Array, Hash_Table, Math, Design, Randomized	1326	68.23
0622	Design Circular Queue	Medium	Array, Design, Linked_List, Queue	234	92.68
0729	My Calendar I	Medium	Binary_Search, Design, Ordered_Set, Segment_Tree	378	69.70

Contributing

Your ideas/fixes/algorithms are more than welcome!

1. Fork this repo
2. Clone your forked repo (git clone https://github.com/YOUR_GITHUB_USERNAME/LeetCode-in-Kotlin.git) onto your local machine
3. cd into your cloned directory, create your feature branch (git checkout -b my-awesome-fix)
4. git add your desired changes to this repo
5. Commit your changes (git commit -m 'Added some awesome features/fixes')
6. Push to the branch (git push origin my-awesome-feature)
7. Open your forked repo on Github website, create a new Pull Request to this repo!