LeetCode-in-Java

Java-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-java</artifactId>
    <version>1.33</version>
  </dependency>
  ...
</dependencies>

Gradle configuration:

implementation 'com.github.javadev:leetcode-in-java:1.33'

"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."

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
SQL I

Level 1

Day 1 Prefix Sum


1480	Running Sum of 1d Array	Easy	Array, Prefix_Sum	0	100.00
0724	Find Pivot Index	Easy	Array, Prefix_Sum	2	69.67

Day 2 String


0205	Isomorphic Strings	Easy	String, Hash_Table	2	99.97
0392	Is Subsequence	Easy	String, Dynamic_Programming, Two_Pointers	1	93.01

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)	0	100.00
0206	Reverse Linked List	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Linked_List, Recursion, Big_O_Time_O(N)_Space_O(1)	0	100.00

Day 4 Linked List


0876	Middle of the Linked List	Easy	Two_Pointers, Linked_List	0	100.00
0142	Linked List Cycle II	Medium	Top_100_Liked_Questions, Hash_Table, Two_Pointers, Linked_List, Big_O_Time_O(N)_Space_O(1)	0	100.00

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)	1	100.00
0409	Longest Palindrome	Easy	String, Hash_Table, Greedy	2	92.90

Day 6 Tree


0589	N-ary Tree Preorder Traversal	Easy	Depth_First_Search, Tree, Stack	1	90.98
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)	1	91.09

Day 7 Binary Search


0704	Binary Search	Easy	Top_100_Liked_Questions, Array, Binary_Search	0	100.00
0278	First Bad Version	Easy	Binary_Search, Interactive	15	87.89

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))	0	100.00
0235	Lowest Common Ancestor of a Binary Search Tree	Medium	Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree	4	100.00

Day 9 Graph/BFS/DFS


0733	Flood Fill	Easy	Array, Depth_First_Search, Breadth_First_Search, Matrix	1	85.36
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(MN)_Space_O(MN)	3	97.76

Day 10 Dynamic Programming


0509	Fibonacci Number	Easy	Dynamic_Programming, Math, Recursion, Memoization	0	100.00
0070	Climbing Stairs	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Math, Memoization, Big_O_Time_O(n)_Space_O(n)	0	100.00

Day 11 Dynamic Programming


0746	Min Cost Climbing Stairs	Easy	Array, Dynamic_Programming	1	86.38
0062	Unique Paths	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Math, Combinatorics, Big_O_Time_O(mn)_Space_O(mn)	0	100.00

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)	6	99.03
0424	Longest Repeating Character Replacement	Medium	String, Hash_Table, Sliding_Window	5	95.15

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)	2	85.97
0299	Bulls and Cows	Medium	String, Hash_Table, Counting	6	86.69

Day 14 Stack


0844	Backspace String Compare	Easy	String, Two_Pointers, Stack, Simulation	0	100.00
0394	Decode String	Medium	Top_100_Liked_Questions, String, Stack, Recursion, Big_O_Time_O(n)_Space_O(n)	1	87.68

Day 15 Heap


1046	Last Stone Weight	Easy	Array, Heap_Priority_Queue	2	73.81
0692	Top K Frequent Words	Medium	String, Hash_Table, Sorting, Heap_Priority_Queue, Counting, Trie, Bucket_Sort	11	38.54

Level 2

Day 1 Implementation/Simulation


0202	Happy Number	Easy	Top_Interview_Questions, Hash_Table, Math, Two_Pointers	1	98.59
0054	Spiral Matrix	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Matrix, Simulation	0	100.00
1706	Where Will the Ball Fall	Medium	Array, Dynamic_Programming, Depth_First_Search, Matrix, Simulation	2	64.55

Day 2 String


0014	Longest Common Prefix	Easy	Top_100_Liked_Questions, Top_Interview_Questions, String	0	100.00
0043	Multiply Strings	Medium	String, Math, Simulation	1	100.00

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)	0	100.00
0234	Palindrome Linked List	Easy	Top_100_Liked_Questions, Two_Pointers, Stack, Linked_List, Recursion, Big_O_Time_O(n)_Space_O(1)	6	76.07

Day 4 Linked List


0328	Odd Even Linked List	Medium	Linked_List	0	100.00
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))	12	85.82

Day 5 Greedy


2131	Longest Palindrome by Concatenating Two Letter Words	Medium	Array, String, Hash_Table, Greedy, Counting	73	76.60
0621	Task Scheduler	Medium	Array, Hash_Table, Sorting, Greedy, Heap_Priority_Queue, Counting	3	84.32

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)	0	100.00
0110	Balanced Binary Tree	Easy	Depth_First_Search, Tree, Binary_Tree	1	98.82

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)	1	65.86
0437	Path Sum III	Medium	Depth_First_Search, Tree, Binary_Tree, Big_O_Time_O(n)_Space_O(n)	18	45.66

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)	0	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)	0	100.00

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	0	100.00
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)	1	78.91
0173	Binary Search Tree Iterator	Medium	Tree, Binary_Tree, Stack, Design, Binary_Search_Tree, Iterator	18	84.18

Day 10 Graph/BFS/DFS


0994	Rotting Oranges	Medium	Top_100_Liked_Questions, Array, Breadth_First_Search, Matrix	3	74.27
0417	Pacific Atlantic Water Flow	Medium	Array, Depth_First_Search, Breadth_First_Search, Matrix	5	92.62

Day 11 Graph/BFS/DFS


0210	Course Schedule II	Medium	Top_Interview_Questions, Depth_First_Search, Breadth_First_Search, Graph, Topological_Sort	13	35.17
0815	Bus Routes	Hard	Array, Hash_Table, Breadth_First_Search	49	89.11

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)	0	100.00
0322	Coin Change	Medium	Top_100_Liked_Questions, Array, Dynamic_Programming, Breadth_First_Search, Big_O_Time_O(m*n)_Space_O(amount)	17	91.77

Day 13 Dynamic Programming


0416	Partition Equal Subset Sum	Medium	Top_100_Liked_Questions, Array, Dynamic_Programming, Big_O_Time_O(nsums)_Space_O(nsums)	27	94.53
0152	Maximum Product Subarray	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(N)_Space_O(1)	1	92.31

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)	2	99.52
0016	3Sum Closest	Medium	Array, Sorting, Two_Pointers	4	98.21
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)	2	99.94

Day 15 Tree


0100	Same Tree	Easy	Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree	0	100.00
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))	0	100.00
0199	Binary Tree Right Side View	Medium	Top_100_Liked_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree	1	94.57

Day 16 Design


0232	Implement Queue using Stacks	Easy	Stack, Design, Queue	1	67.21
0155	Min Stack	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Stack, Design, Big_O_Time_O(1)_Space_O(N)	3	100.00
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)	34	99.90

Day 17 Interval


0057	Insert Interval	Medium	Array	0	100.00
0056	Merge Intervals	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Big_O_Time_O(n_log_n)_Space_O(n)	8	96.27

Day 18 Stack


0735	Asteroid Collision	Medium	Array, Stack	2	99.59
0227	Basic Calculator II	Medium	String, Math, Stack	8	95.32

Day 19 Union Find


0547	Number of Provinces	Medium	Depth_First_Search, Breadth_First_Search, Graph, Union_Find	2	69.51
0947	Most Stones Removed with Same Row or Column	Medium	Depth_First_Search, Graph, Union_Find	7	98.83

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)	1	100.00
0046	Permutations	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Backtracking, Big_O_Time_O(n*n!)_Space_O(n+n!)	1	95.07

Udemy

Udemy Integers


0412	Fizz Buzz	Easy	String, Math, Simulation	1	100.00
0136	Single Number	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Array, Bit_Manipulation, Big_O_Time_O(N)_Space_O(1)	1	99.97
0007	Reverse Integer	Medium	Top_Interview_Questions, Math	1	96.61
0009	Palindrome Number	Easy	Math	5	77.91
0172	Factorial Trailing Zeroes	Medium	Top_Interview_Questions, Math	1	85.61
0050	Pow(x, n)	Medium	Top_Interview_Questions, Math, Recursion	0	100.00

Udemy Strings


0344	Reverse String	Easy	String, Two_Pointers, Recursion	1	99.91
0014	Longest Common Prefix	Easy	Top_100_Liked_Questions, Top_Interview_Questions, String	0	100.00
0187	Repeated DNA Sequences	Medium	String, Hash_Table, Bit_Manipulation, Sliding_Window, Hash_Function, Rolling_Hash	29	77.11
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)	2	99.52
0020	Valid Parentheses	Easy	Top_100_Liked_Questions, Top_Interview_Questions, String, Stack, Big_O_Time_O(n)_Space_O(n)	1	98.78
0005	Longest Palindromic Substring	Medium	Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Big_O_Time_O(n)_Space_O(n)	7	96.96
0394	Decode String	Medium	Top_100_Liked_Questions, String, Stack, Recursion, Big_O_Time_O(n)_Space_O(n)	1	87.68
0242	Valid Anagram	Easy	String, Hash_Table, Sorting	2	99.01
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)	6	92.28
0151	Reverse Words in a String	Medium	String, Two_Pointers	2	99.94
0273	Integer to English Words	Hard	String, Math, Recursion	3	95.67

Udemy Binary Search


0704	Binary Search	Easy	Top_100_Liked_Questions, Array, Binary_Search	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)	100.00
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)	100.00

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)	1	100.00
0283	Move Zeroes	Easy	Top_100_Liked_Questions, Array, Two_Pointers, Big_O_Time_O(n)_Space_O(1)	2	79.54
0001	Two Sum	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Big_O_Time_O(n)_Space_O(n)	2	85.97
0217	Contains Duplicate	Easy	Top_Interview_Questions, Array, Hash_Table, Sorting	6	96.68
0058	Length of Last Word	Easy	String	0	100.00
0605	Can Place Flowers	Easy	Array, Greedy	1	96.77
0122	Best Time to Buy and Sell Stock II	Medium	Top_Interview_Questions, Array, Dynamic_Programming, Greedy	1	96.82
0080	Remove Duplicates from Sorted Array II	Medium	Array, Two_Pointers	0	100.00
0189	Rotate Array	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Math, Two_Pointers, Big_O_Time_O(n)_Space_O(1)	0	100.00
0055	Jump Game	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Greedy, Big_O_Time_O(n)_Space_O(1)	2	79.47
0075	Sort Colors	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Two_Pointers, Big_O_Time_O(n)_Space_O(1)	0	100.00
0066	Plus One	Easy	Top_Interview_Questions, Array, Math	0	100.00
0238	Product of Array Except Self	Medium	Top_100_Liked_Questions, Array, Prefix_Sum, Big_O_Time_O(n^2)_Space_O(n)	1	100.00
1291	Sequential Digits	Medium	Enumeration	0	100.00
0448	Find All Numbers Disappeared in an Array	Easy	Array, Hash_Table	3	100.00
0442	Find All Duplicates in an Array	Medium	Array, Hash_Table	5	98.83
0041	First Missing Positive	Hard	Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Big_O_Time_O(n)_Space_O(n)	2	57.59
0697	Degree of an Array	Easy	Array, Hash_Table	14	93.19
0532	K-diff Pairs in an Array	Medium	Array, Hash_Table, Sorting, Binary_Search, Two_Pointers	13	58.23
0713	Subarray Product Less Than K	Medium	Array, Sliding_Window	8	39.00
1007	Minimum Domino Rotations For Equal Row	Medium	Array, Greedy	5	79.64
1306	Jump Game III	Medium	Array, Depth_First_Search, Breadth_First_Search	2	96.23
0456	132 Pattern	Medium	Array, Binary_Search, Stack, Ordered_Set, Monotonic_Stack	16	82.41
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)	58	52.28

Udemy Two Pointers


0392	Is Subsequence	Easy	String, Dynamic_Programming, Two_Pointers	1	93.01
0125	Valid Palindrome	Easy	Top_Interview_Questions, String, Two_Pointers	3	98.64
0977	Squares of a Sorted Array	Easy	Array, Sorting, Two_Pointers	1	100.00
0026	Remove Duplicates from Sorted Array	Easy	Top_Interview_Questions, Array, Two_Pointers	1	98.56
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)	0	100.00
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)	29	82.24

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)	1	100.00
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)	1	100.00

Udemy Sorting Algorithms


0912	Sort an Array	Medium	Array, Sorting, Heap_Priority_Queue, Divide_and_Conquer, Merge_Sort, Bucket_Sort, Counting_Sort, Radix_Sort	25	38.15

Udemy 2D Arrays/Matrix


0304	Range Sum Query 2D - Immutable	Medium	Array, Matrix, Design, Prefix_Sum	153	87.51
0074	Search a 2D Matrix	Medium	Top_100_Liked_Questions, Array, Binary_Search, Matrix, Big_O_Time_O(endRow+endCol)_Space_O(1)	0	100.00
0054	Spiral Matrix	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Matrix, Simulation	0	100.00
0048	Rotate Image	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Math, Matrix, Big_O_Time_O(n^2)_Space_O(1)	0	100.00
1572	Matrix Diagonal Sum	Easy	Array, Matrix	0	100.00
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)	1	79.07
0056	Merge Intervals	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Big_O_Time_O(n_log_n)_Space_O(n)	8	96.27

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)	1	75.27
0445	Add Two Numbers II	Medium	Math, Stack, Linked_List	3	90.38
0328	Odd Even Linked List	Medium	Linked_List	0	100.00
0061	Rotate List	Medium	Two_Pointers, Linked_List	0	100.00
0024	Swap Nodes in Pairs	Medium	Top_100_Liked_Questions, Linked_List, Recursion, Big_O_Time_O(n)_Space_O(1)	0	100.00
0876	Middle of the Linked List	Easy	Two_Pointers, Linked_List	0	100.00
0142	Linked List Cycle II	Medium	Top_100_Liked_Questions, Hash_Table, Two_Pointers, Linked_List, Big_O_Time_O(N)_Space_O(1)	0	100.00
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)	0	100.00
0206	Reverse Linked List	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Linked_List, Recursion, Big_O_Time_O(N)_Space_O(1)	0	100.00
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)	0	100.00
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)	1	99.68
0234	Palindrome Linked List	Easy	Top_100_Liked_Questions, Two_Pointers, Stack, Linked_List, Recursion, Big_O_Time_O(n)_Space_O(1)	6	76.07
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)	0	100.00
0025	Reverse Nodes in k-Group	Hard	Top_100_Liked_Questions, Linked_List, Recursion, Big_O_Time_O(n)_Space_O(k)	0	100.00
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)	87	50.80
0707	Design Linked List	Medium	Design, Linked_List	10	70.60

Udemy Tree Stack Queue


0144	Binary Tree Preorder Traversal	Easy	Depth_First_Search, Tree, Binary_Tree, Stack	1	48.38
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)	0	100.00
0145	Binary Tree Postorder Traversal	Easy	Depth_First_Search, Tree, Binary_Tree, Stack	1	49.11
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)	1	91.09
0103	Binary Tree Zigzag Level Order Traversal	Medium	Top_Interview_Questions, Breadth_First_Search, Tree, Binary_Tree	1	95.00
0108	Convert Sorted Array to Binary Search Tree	Easy	Top_Interview_Questions, Array, Tree, Binary_Tree, Binary_Search_Tree, Divide_and_Conquer	0	100.00
1008	Construct Binary Search Tree from Preorder Traversal	Medium	Array, Tree, Binary_Tree, Stack, Monotonic_Stack, Binary_Search_Tree	0	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)	1	65.86
0938	Range Sum of BST	Easy	Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree	0	100.00
0100	Same Tree	Easy	Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree	0	100.00
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)	0	100.00
0111	Minimum Depth of Binary Tree	Easy	Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree	1	97.49
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)	0	100.00
0110	Balanced Binary Tree	Easy	Depth_First_Search, Tree, Binary_Tree	1	98.82
0701	Insert into a Binary Search Tree	Medium	Tree, Binary_Tree, Binary_Search_Tree	0	100.00
0297	Serialize and Deserialize Binary Tree	Hard	String, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Design	7	98.13
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)	1	99.46
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))	0	100.00
0337	House Robber III	Medium	Dynamic_Programming, Depth_First_Search, Tree, Binary_Tree	1	91.77
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)	10	56.51
0968	Binary Tree Cameras	Hard	Dynamic_Programming, Depth_First_Search, Tree, Binary_Tree	0	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)	34	99.90
0745	Prefix and Suffix Search	Hard	String, Design, Trie	366	76.15

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(MN)_Space_O(MN)	3	97.76
0133	Clone Graph	Medium	Hash_Table, Depth_First_Search, Breadth_First_Search, Graph	45	29.80
0417	Pacific Atlantic Water Flow	Medium	Array, Depth_First_Search, Breadth_First_Search, Matrix	5	92.62

Udemy Dynamic Programming


0120	Triangle	Medium	Array, Dynamic_Programming	2	94.63
0118	Pascal's Triangle	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming	1	67.08
0119	Pascal's Triangle II	Easy	Array, Dynamic_Programming	0	100.00
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)	2	97.08
0152	Maximum Product Subarray	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(N)_Space_O(1)	1	92.31
0198	House Robber	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(n)_Space_O(n)	0	100.00
0213	House Robber II	Medium	Array, Dynamic_Programming	0	100.00
0509	Fibonacci Number	Easy	Dynamic_Programming, Math, Recursion, Memoization	0	100.00
0070	Climbing Stairs	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Math, Memoization, Big_O_Time_O(n)_Space_O(n)	0	100.00
0064	Minimum Path Sum	Medium	Top_100_Liked_Questions, Array, Dynamic_Programming, Matrix, Big_O_Time_O(mn)_Space_O(mn)	0	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)	3	98.63
1143	Longest Common Subsequence	Medium	Top_100_Liked_Questions, String, Dynamic_Programming, Big_O_Time_O(nm)_Space_O(nm)	33	46.23
0072	Edit Distance	Medium	Top_100_Liked_Questions, String, Dynamic_Programming, Big_O_Time_O(n^2)_Space_O(n2)	4	90.13
0044	Wildcard Matching	Hard	Top_Interview_Questions, String, Dynamic_Programming, Greedy, Recursion	2	99.87
0010	Regular Expression Matching	Hard	Top_Interview_Questions, String, Dynamic_Programming, Recursion, Big_O_Time_O(mn)_Space_O(mn)	1	100.00

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)	0	100.00
0039	Combination Sum	Medium	Top_100_Liked_Questions, Array, Backtracking, Big_O_Time_O(2^n)_Space_O(n+2^n)	1	100.00
0216	Combination Sum III	Medium	Array, Backtracking	1	81.35
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)	1	70.60
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)	0	100.00
0046	Permutations	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Backtracking, Big_O_Time_O(n*n!)_Space_O(n+n!)	1	95.07

Udemy Bit Manipulation


0191	Number of 1 Bits	Easy	Top_Interview_Questions, Bit_Manipulation	1	84.87
0389	Find the Difference	Easy	String, Hash_Table, Sorting, Bit_Manipulation	1	100.00
0190	Reverse Bits	Easy	Top_Interview_Questions, Bit_Manipulation, Divide_and_Conquer	1	98.66
0461	Hamming Distance	Easy	Bit_Manipulation	0	100.00
1009	Complement of Base 10 Integer	Easy	Bit_Manipulation	1	41.56
0338	Counting Bits	Easy	Dynamic_Programming, Bit_Manipulation, Big_O_Time_O(num)_Space_O(num)	2	86.73
0371	Sum of Two Integers	Medium	Math, Bit_Manipulation	0	100.00
0029	Divide Two Integers	Medium	Top_Interview_Questions, Math, Bit_Manipulation	1	97.44

Udemy Design


0155	Min Stack	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Stack, Design, Big_O_Time_O(1)_Space_O(N)	3	100.00

Data Structure I

Day 1 Array


0217	Contains Duplicate	Easy	Top_Interview_Questions, Array, Hash_Table, Sorting	6	96.68
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)	1	100.00

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)	2	85.97
0088	Merge Sorted Array	Easy	Top_Interview_Questions, Array, Sorting, Two_Pointers	0	100.00

Day 3 Array


0350	Intersection of Two Arrays II	Easy	Array, Hash_Table, Sorting, Binary_Search, Two_Pointers	4	69.62
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)	1	100.00

Day 4 Array


0566	Reshape the Matrix	Easy	Array, Matrix, Simulation	1	90.08
0118	Pascal's Triangle	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming	1	67.08

Day 5 Array


0036	Valid Sudoku	Medium	Top_Interview_Questions, Array, Hash_Table, Matrix	1	100.00
0074	Search a 2D Matrix	Medium	Top_100_Liked_Questions, Array, Binary_Search, Matrix, Big_O_Time_O(endRow+endCol)_Space_O(1)	0	100.00

Day 6 String


0387	First Unique Character in a String	Easy	String, Hash_Table, Counting, Queue	1	100.00
0383	Ransom Note	Easy	String, Hash_Table, Counting	1	99.97
0242	Valid Anagram	Easy	String, Hash_Table, Sorting	2	99.01

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)	0	100.00
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)	0	100.00
0203	Remove Linked List Elements	Easy	Linked_List, Recursion	1	98.82

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)	0	100.00
0083	Remove Duplicates from Sorted List	Easy	Linked_List	0	100.00

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)	1	98.78
0232	Implement Queue using Stacks	Easy	Stack, Design, Queue	1	67.21

Day 10 Tree


0144	Binary Tree Preorder Traversal	Easy	Depth_First_Search, Tree, Binary_Tree, Stack	1	48.38
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)	0	100.00
0145	Binary Tree Postorder Traversal	Easy	Depth_First_Search, Tree, Binary_Tree, Stack	1	49.11

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)	1	91.09
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)	0	100.00
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))	0	100.00

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)	0	100.00
0112	Path Sum	Easy	Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree	0	100.00

Day 13 Tree


0700	Search in a Binary Search Tree	Easy	Tree, Binary_Tree, Binary_Search_Tree	0	100.00
0701	Insert into a Binary Search Tree	Medium	Tree, Binary_Tree, Binary_Search_Tree	0	100.00

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))	0	100.00
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	5	74.23
0235	Lowest Common Ancestor of a Binary Search Tree	Medium	Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree	4	100.00

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)	1	99.97
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)	1	100.00
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)	29	82.24

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)	0	100.00
0056	Merge Intervals	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Big_O_Time_O(n_log_n)_Space_O(n)	8	96.27
0706	Design HashMap	Easy	Array, Hash_Table, Design, Linked_List, Hash_Function	13	95.71

Day 3 Array


0119	Pascal's Triangle II	Easy	Array, Dynamic_Programming	100.00
0048	Rotate Image	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Math, Matrix, Big_O_Time_O(n^2)_Space_O(1)	100.00
0059	Spiral Matrix II	Medium	Array, Matrix, Simulation	100.00

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)	7	86.73
0435	Non-overlapping Intervals	Medium	Array, Dynamic_Programming, Sorting, Greedy	96	47.37

Day 5 Array


0334	Increasing Triplet Subsequence	Medium	Array, Greedy	2	99.33
0238	Product of Array Except Self	Medium	Top_100_Liked_Questions, Array, Prefix_Sum, Big_O_Time_O(n^2)_Space_O(n)	1	100.00
0560	Subarray Sum Equals K	Medium	Top_100_Liked_Questions, Array, Hash_Table, Prefix_Sum, Big_O_Time_O(n)_Space_O(n)	21	98.97

Day 6 String


0415	Add Strings	Easy	String, Math, Simulation	3	82.41
0409	Longest Palindrome	Easy	String, Hash_Table, Greedy	2	92.90

Day 7 String


0290	Word Pattern	Easy	String, Hash_Table	1	97.26
0763	Partition Labels	Medium	String, Hash_Table, Greedy, Two_Pointers, Big_O_Time_O(n)_Space_O(1)	1	100.00

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)	6	92.28
0043	Multiply Strings	Medium	String, Math, Simulation	1	100.00

Day 9 String


0187	Repeated DNA Sequences	Medium	String, Hash_Table, Bit_Manipulation, Sliding_Window, Hash_Function, Rolling_Hash	29	77.11
0005	Longest Palindromic Substring	Medium	Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Big_O_Time_O(n)_Space_O(n)	7	96.96

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))	1	100.00
0142	Linked List Cycle II	Medium	Top_100_Liked_Questions, Hash_Table, Two_Pointers, Linked_List, Big_O_Time_O(N)_Space_O(1)	0	100.00

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)	1	99.68
0082	Remove Duplicates from Sorted List II	Medium	Two_Pointers, Linked_List	0	100.00

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)	0	100.00
0707	Design Linked List	Medium	Design, Linked_List	10	70.60

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)	0	100.00
0143	Reorder List	Medium	Two_Pointers, Stack, Linked_List, Recursion	2	72.59

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)	3	100.00
1249	Minimum Remove to Make Valid Parentheses	Medium	String, Stack	13	94.62
1823	Find the Winner of the Circular Game	Medium	Array, Math, Simulation, Recursion, Queue	3	64.85

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	0	100.00
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)	3	86.35
0103	Binary Tree Zigzag Level Order Traversal	Medium	Top_Interview_Questions, Breadth_First_Search, Tree, Binary_Tree	1	95.00

Day 16 Tree


0199	Binary Tree Right Side View	Medium	Top_100_Liked_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree	1	94.57
0113	Path Sum II	Medium	Depth_First_Search, Tree, Binary_Tree, Backtracking	1	100.00
0450	Delete Node in a BST	Medium	Tree, Binary_Tree, Binary_Search_Tree	0	100.00

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)	1	78.91
0173	Binary Search Tree Iterator	Medium	Tree, Binary_Tree, Stack, Design, Binary_Search_Tree, Iterator	18	84.18

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)	10	56.51
0297	Serialize and Deserialize Binary Tree	Hard	String, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Design	7	98.13

Day 19 Graph


0997	Find the Town Judge	Easy	Array, Hash_Table, Graph	3	80.64
1557	Minimum Number of Vertices to Reach All Nodes	Medium	Graph	8	99.94
0841	Keys and Rooms	Medium	Depth_First_Search, Breadth_First_Search, Graph	3	51.54

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))	5	70.82
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)	9	97.93

Day 21 Heap Priority Queue


0451	Sort Characters By Frequency	Medium	String, Hash_Table, Sorting, Heap_Priority_Queue, Counting, Bucket_Sort	13	89.63
0973	K Closest Points to Origin	Medium	Array, Math, Sorting, Heap_Priority_Queue, Divide_and_Conquer, Geometry, Quickselect	4	98.26

Algorithm I

Day 1 Binary Search


0704	Binary Search	Easy	Top_100_Liked_Questions, Array, Binary_Search	0	100.00
0278	First Bad Version	Easy	Binary_Search, Interactive	15	87.89
0035	Search Insert Position	Easy	Top_100_Liked_Questions, Array, Binary_Search, Big_O_Time_O(log_n)_Space_O(1)	0	100.00

Day 2 Two Pointers


0977	Squares of a Sorted Array	Easy	Array, Sorting, Two_Pointers	1	100.00
0189	Rotate Array	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Math, Two_Pointers, Big_O_Time_O(n)_Space_O(1)	0	100.00

Day 3 Two Pointers


0283	Move Zeroes	Easy	Top_100_Liked_Questions, Array, Two_Pointers, Big_O_Time_O(n)_Space_O(1)	2	79.54
0167	Two Sum II - Input Array Is Sorted	Medium	Array, Binary_Search, Two_Pointers	1	99.21

Day 4 Two Pointers


0344	Reverse String	Easy	String, Two_Pointers, Recursion	1	99.91
0557	Reverse Words in a String III	Easy	String, Two_Pointers	4	97.75

Day 5 Two Pointers


0876	Middle of the Linked List	Easy	Two_Pointers, Linked_List	0	100.00
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)	0	100.00

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)	2	99.52
0567	Permutation in String	Medium	Top_100_Liked_Questions, String, Hash_Table, Two_Pointers, Sliding_Window	5	93.93

Day 7 Breadth First Search Depth First Search


0733	Flood Fill	Easy	Array, Depth_First_Search, Breadth_First_Search, Matrix	1	85.36
0695	Max Area of Island	Medium	Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find	3	76.79

Day 8 Breadth First Search Depth First Search


0617	Merge Two Binary Trees	Easy	Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree	1	72.47
0116	Populating Next Right Pointers in Each Node	Medium	Top_Interview_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Linked_List	0	100.00

Day 9 Breadth First Search Depth First Search


0542	01 Matrix	Medium	Array, Dynamic_Programming, Breadth_First_Search, Matrix	7	95.83
0994	Rotting Oranges	Medium	Top_100_Liked_Questions, Array, Breadth_First_Search, Matrix	3	74.27

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)	0	100.00
0206	Reverse Linked List	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Linked_List, Recursion, Big_O_Time_O(N)_Space_O(1)	0	100.00

Day 11 Recursion Backtracking


0077	Combinations	Medium	Backtracking	11	77.40
0046	Permutations	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Backtracking, Big_O_Time_O(n*n!)_Space_O(n+n!)	1	95.07
0784	Letter Case Permutation	Medium	String, Bit_Manipulation, Backtracking	10	40.38

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)	0	100.00
0198	House Robber	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(n)_Space_O(n)	0	100.00
0120	Triangle	Medium	Array, Dynamic_Programming	2	94.63

Day 13 Bit Manipulation


0231	Power of Two	Easy	Math, Bit_Manipulation, Recursion	1	100.00
0191	Number of 1 Bits	Easy	Top_Interview_Questions, Bit_Manipulation	1	84.87

Day 14 Bit Manipulation


0190	Reverse Bits	Easy	Top_Interview_Questions, Bit_Manipulation, Divide_and_Conquer	1	98.66
0136	Single Number	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Array, Bit_Manipulation, Big_O_Time_O(N)_Space_O(1)	1	99.97

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)	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)	100.00
0074	Search a 2D Matrix	Medium	Top_100_Liked_Questions, Array, Binary_Search, Matrix, Big_O_Time_O(endRow+endCol)_Space_O(1)	100.00

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)	0	100.00
0162	Find Peak Element	Medium	Top_Interview_Questions, Array, Binary_Search	0	100.00

Day 3 Two Pointers


0082	Remove Duplicates from Sorted List II	Medium	Two_Pointers, Linked_List	0	100.00
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)	29	82.24

Day 4 Two Pointers


0844	Backspace String Compare	Easy	String, Two_Pointers, Stack, Simulation	0	100.00
0986	Interval List Intersections	Medium	Array, Two_Pointers	2	99.95
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)	3	95.71

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)	6	99.03
0713	Subarray Product Less Than K	Medium	Array, Sliding_Window	8	39.00
0209	Minimum Size Subarray Sum	Medium	Array, Binary_Search, Prefix_Sum, Sliding_Window	1	100.00

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(MN)_Space_O(MN)	3	97.76
0547	Number of Provinces	Medium	Depth_First_Search, Breadth_First_Search, Graph, Union_Find	2	69.51

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	0	100.00
0572	Subtree of Another Tree	Easy	Depth_First_Search, Tree, Binary_Tree, Hash_Function, String_Matching	1	100.00

Day 8 Breadth First Search Depth First Search


1091	Shortest Path in Binary Matrix	Medium	Array, Breadth_First_Search, Matrix	22	69.99
0130	Surrounded Regions	Medium	Top_Interview_Questions, Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find	2	84.66
0797	All Paths From Source to Target	Medium	Depth_First_Search, Breadth_First_Search, Graph, Backtracking	2	90.53

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)	1	70.60
0090	Subsets II	Medium	Array, Bit_Manipulation, Backtracking	2	82.94

Day 10 Recursion Backtracking


0047	Permutations II	Medium	Array, Backtracking	1	99.86
0039	Combination Sum	Medium	Top_100_Liked_Questions, Array, Backtracking, Big_O_Time_O(2^n)_Space_O(n+2^n)	1	100.00
0040	Combination Sum II	Medium	Array, Backtracking	2	99.75

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)	0	100.00
0022	Generate Parentheses	Medium	Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Backtracking, Big_O_Time_O(2^n)_Space_O(n)	0	100.00
0079	Word Search	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Matrix, Backtracking, Big_O_Time_O(4^(mn))_Space_O(mn)	157	78.97

Day 12 Dynamic Programming


0213	House Robber II	Medium	Array, Dynamic_Programming	0	100.00
0055	Jump Game	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Greedy, Big_O_Time_O(n)_Space_O(1)	2	79.47

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)	2	49.02
0062	Unique Paths	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Math, Combinatorics, Big_O_Time_O(mn)_Space_O(mn)	0	100.00

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)	7	96.96
0413	Arithmetic Slices	Medium	Array, Dynamic_Programming	0	100.00

Day 15 Dynamic Programming


0091	Decode Ways	Medium	Top_Interview_Questions, String, Dynamic_Programming	2	66.37
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)	2	97.08

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)	3	98.63
0673	Number of Longest Increasing Subsequence	Medium	Array, Dynamic_Programming, Segment_Tree, Binary_Indexed_Tree	25	68.75

Day 17 Dynamic Programming


1143	Longest Common Subsequence	Medium	Top_100_Liked_Questions, String, Dynamic_Programming, Big_O_Time_O(nm)_Space_O(nm)	33	46.23
0583	Delete Operation for Two Strings	Medium	String, Dynamic_Programming	12	79.10

Day 18 Dynamic Programming


0072	Edit Distance	Medium	Top_100_Liked_Questions, String, Dynamic_Programming, Big_O_Time_O(n^2)_Space_O(n2)	4	90.13
0322	Coin Change	Medium	Top_100_Liked_Questions, Array, Dynamic_Programming, Breadth_First_Search, Big_O_Time_O(m*n)_Space_O(amount)	17	91.77
0343	Integer Break	Medium	Dynamic_Programming, Math	0	100.00

Day 19 Bit Manipulation


0201	Bitwise AND of Numbers Range	Medium	Bit_Manipulation	8	74.15

Day 20 Others


0384	Shuffle an Array	Medium	Array, Math, Randomized	52	91.77

Day 21 Others


0202	Happy Number	Easy	Top_Interview_Questions, Hash_Table, Math, Two_Pointers	1	98.59
0149	Max Points on a Line	Hard	Top_Interview_Questions, Array, Hash_Table, Math, Geometry	11	99.21

Binary Search I

Day 1


0704	Binary Search	Easy	Top_100_Liked_Questions, Array, Binary_Search	0	100.00
0374	Guess Number Higher or Lower	Easy	Binary_Search, Interactive	0	100.00

Day 2


0035	Search Insert Position	Easy	Top_100_Liked_Questions, Array, Binary_Search, Big_O_Time_O(log_n)_Space_O(1)	0	100.00
0852	Peak Index in a Mountain Array	Medium	Array, Binary_Search	0	100.00

Day 3


0367	Valid Perfect Square	Easy	Math, Binary_Search	0	100.00
1385	Find the Distance Value Between Two Arrays	Easy	Array, Sorting, Binary_Search, Two_Pointers	5	65.78

Day 4


0069	Sqrt(x)	Easy	Top_Interview_Questions, Math, Binary_Search	1	99.51
0744	Find Smallest Letter Greater Than Target	Easy	Array, Binary_Search	0	100.00

Day 5


0278	First Bad Version	Easy	Binary_Search, Interactive	15	87.89
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)	0	100.00

Day 6


0441	Arranging Coins	Easy	Math, Binary_Search	2	95.97
1539	Kth Missing Positive Number	Easy	Array, Binary_Search	0	100.00

Day 7


0167	Two Sum II - Input Array Is Sorted	Medium	Array, Binary_Search, Two_Pointers	1	99.21
1608	Special Array With X Elements Greater Than or Equal X	Easy	Array, Sorting, Binary_Search	2	61.14

Day 8


1351	Count Negative Numbers in a Sorted Matrix	Easy	Array, Binary_Search, Matrix	1	49.66
0074	Search a 2D Matrix	Medium	Top_100_Liked_Questions, Array, Binary_Search, Matrix, Big_O_Time_O(endRow+endCol)_Space_O(1)	0	100.00

Day 9


1337	The K Weakest Rows in a Matrix	Easy	Array, Sorting, Binary_Search, Matrix, Heap_Priority_Queue	1	99.77
1346	Check If N and Its Double Exist	Easy	Array, Hash_Table, Sorting, Binary_Search, Two_Pointers	1	99.64

Day 10


0350	Intersection of Two Arrays II	Easy	Array, Hash_Table, Sorting, Binary_Search, Two_Pointers	4	69.62
0633	Sum of Square Numbers	Medium	Math, Binary_Search, Two_Pointers	4	82.92

Day 11


1855	Maximum Distance Between a Pair of Values	Medium	Array, Greedy, Binary_Search, Two_Pointers	4	62.20
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)	0	100.00

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)	0	100.00

Binary Search II

Day 1


0209	Minimum Size Subarray Sum	Medium	Array, Binary_Search, Prefix_Sum, Sliding_Window	1	100.00
0611	Valid Triangle Number	Medium	Array, Sorting, Greedy, Binary_Search, Two_Pointers	10	100.00

Day 2


0658	Find K Closest Elements	Medium	Array, Sorting, Binary_Search, Two_Pointers, Heap_Priority_Queue	3	99.20
1894	Find the Student that Will Replace the Chalk	Medium	Array, Binary_Search, Simulation, Prefix_Sum	2	76.67

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)	3	98.63
1760	Minimum Limit of Balls in a Bag	Medium	Array, Binary_Search	44	78.49

Day 4


0875	Koko Eating Bananas	Medium	Array, Binary_Search	15	91.32
1552	Magnetic Force Between Two Balls	Medium	Array, Sorting, Binary_Search	39	99.65

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)	2	99.82
1283	Find the Smallest Divisor Given a Threshold	Medium	Array, Binary_Search	9	95.49

Day 6


1898	Maximum Number of Removable Characters	Medium	Array, String, Binary_Search	121	72.51
1870	Minimum Speed to Arrive on Time	Medium	Array, Binary_Search	86	88.58

Day 7


1482	Minimum Number of Days to Make m Bouquets	Medium	Array, Binary_Search	25	69.18
1818	Minimum Absolute Sum Difference	Medium	Array, Sorting, Binary_Search, Ordered_Set	13	99.44

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)	7	86.73
0275	H-Index II	Medium	Array, Binary_Search	0	100.00

Day 9


1838	Frequency of the Most Frequent Element	Medium	Array, Sorting, Greedy, Binary_Search, Prefix_Sum, Sliding_Window	11	100.00
0540	Single Element in a Sorted Array	Medium	Array, Binary_Search	0	100.00

Day 10


0222	Count Complete Tree Nodes	Easy	Depth_First_Search, Tree, Binary_Search, Binary_Tree	0	100.00
1712	Ways to Split Array Into Three Subarrays	Medium	Array, Binary_Search, Two_Pointers, Prefix_Sum	16	84.24

Day 11


0826	Most Profit Assigning Work	Medium	Array, Sorting, Greedy, Binary_Search, Two_Pointers	21	83.83
0436	Find Right Interval	Medium	Array, Sorting, Binary_Search	20	81.51

Day 12


0081	Search in Rotated Sorted Array II	Medium	Array, Binary_Search	1	82.83
0162	Find Peak Element	Medium	Top_Interview_Questions, Array, Binary_Search	0	100.00

Day 13


0154	Find Minimum in Rotated Sorted Array II	Hard	Array, Binary_Search	1	77.09
0528	Random Pick with Weight	Medium	Math, Binary_Search, Prefix_Sum, Randomized	42	50.90

Day 14


1508	Range Sum of Sorted Subarray Sums	Medium	Array, Sorting, Binary_Search, Two_Pointers	60	93.84
1574	Shortest Subarray to be Removed to Make Array Sorted	Medium	Array, Binary_Search, Two_Pointers, Stack, Monotonic_Stack	2	84.97

Day 15


1292	Maximum Side Length of a Square with Sum Less than or Equal to Threshold	Medium	Array, Binary_Search, Matrix, Prefix_Sum	23	32.97
1498	Number of Subsequences That Satisfy the Given Sum Condition	Medium	Array, Sorting, Binary_Search, Two_Pointers	27	99.13

Day 16


0981	Time Based Key-Value Store	Medium	String, Hash_Table, Binary_Search, Design	239	72.78
1300	Sum of Mutated Array Closest to Target	Medium	Array, Sorting, Binary_Search	7	33.33

Day 17


1802	Maximum Value at a Given Index in a Bounded Array	Medium	Greedy, Binary_Search	2	58.44
1901	Find a Peak Element II	Medium	Array, Binary_Search, Matrix, Divide_and_Conquer	0	100.00

Day 18


1146	Snapshot Array	Medium	Array, Hash_Table, Binary_Search, Design	68	45.86
1488	Avoid Flood in The City	Medium	Array, Hash_Table, Greedy, Binary_Search, Heap_Priority_Queue	82	75.08

Day 19


1562	Find Latest Group of Size M	Medium	Array, Binary_Search, Simulation	8	90.00
1648	Sell Diminishing-Valued Colored Balls	Medium	Array, Math, Sorting, Greedy, Binary_Search, Heap_Priority_Queue	27	80.64

Day 20


1201	Ugly Number III	Medium	Math, Binary_Search, Number_Theory	0	100.00
0911	Online Election	Medium	Array, Hash_Table, Binary_Search, Design	63	98.81

Dynamic Programming I

Day 1


0509	Fibonacci Number	Easy	Dynamic_Programming, Math, Recursion, Memoization	0	100.00
1137	N-th Tribonacci Number	Easy	Dynamic_Programming, Math, Memoization	0	100.00

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)	0	100.00
0746	Min Cost Climbing Stairs	Easy	Array, Dynamic_Programming	1	86.38

Day 3


0198	House Robber	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(n)_Space_O(n)	0	100.00
0213	House Robber II	Medium	Array, Dynamic_Programming	0	100.00
0740	Delete and Earn	Medium	Array, Hash_Table, Dynamic_Programming	4	77.68

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)	2	79.47
0045	Jump Game II	Medium	Top_100_Liked_Questions, Array, Dynamic_Programming, Greedy, Big_O_Time_O(n)_Space_O(1)	2	49.02

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)	1	100.00
0918	Maximum Sum Circular Subarray	Medium	Array, Dynamic_Programming, Divide_and_Conquer, Queue, Monotonic_Queue	3	92.86

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)	1	92.31
1567	Maximum Length of Subarray With Positive Product	Medium	Array, Dynamic_Programming, Greedy	4	80.86

Day 7


1014	Best Sightseeing Pair	Medium	Array, Dynamic_Programming	2	99.86
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)	1	100.00
0122	Best Time to Buy and Sell Stock II	Medium	Top_Interview_Questions, Array, Dynamic_Programming, Greedy	1	96.82

Day 8


0309	Best Time to Buy and Sell Stock with Cooldown	Medium	Array, Dynamic_Programming	0	100.00
0714	Best Time to Buy and Sell Stock with Transaction Fee	Medium	Array, Dynamic_Programming, Greedy	4	78.57

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)	2	97.08
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)	0	100.00

Day 10


0413	Arithmetic Slices	Medium	Array, Dynamic_Programming	0	100.00
0091	Decode Ways	Medium	Top_Interview_Questions, String, Dynamic_Programming	2	66.37

Day 11


0264	Ugly Number II	Medium	Hash_Table, Dynamic_Programming, Math, Heap_Priority_Queue	2	99.91
0096	Unique Binary Search Trees	Medium	Dynamic_Programming, Math, Tree, Binary_Tree, Binary_Search_Tree, Big_O_Time_O(n)_Space_O(1)	0	100.00

Day 12


0118	Pascal's Triangle	Easy	Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming	1	67.08
0119	Pascal's Triangle II	Easy	Array, Dynamic_Programming	0	100.00

Day 13


0931	Minimum Falling Path Sum	Medium	Array, Dynamic_Programming, Matrix	4	72.19
0120	Triangle	Medium	Array, Dynamic_Programming	2	94.63

Day 14


1314	Matrix Block Sum	Medium	Array, Matrix, Prefix_Sum	5	67.46
0304	Range Sum Query 2D - Immutable	Medium	Array, Matrix, Design, Prefix_Sum	153	87.51

Day 15


0062	Unique Paths	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Math, Combinatorics, Big_O_Time_O(mn)_Space_O(mn)	0	100.00
0063	Unique Paths II	Medium	Array, Dynamic_Programming, Matrix	0	100.00

Day 16


0064	Minimum Path Sum	Medium	Top_100_Liked_Questions, Array, Dynamic_Programming, Matrix, Big_O_Time_O(mn)_Space_O(mn)	0	100.00
0221	Maximal Square	Medium	Array, Dynamic_Programming, Matrix, Big_O_Time_O(mn)_Space_O(mn)	7	72.35

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)	7	96.96
0516	Longest Palindromic Subsequence	Medium	String, Dynamic_Programming	88	58.87

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)	3	98.63
0376	Wiggle Subsequence	Medium	Array, Dynamic_Programming, Greedy	0	100.00

Day 19


0392	Is Subsequence	Easy	String, Dynamic_Programming, Two_Pointers	1	93.01
1143	Longest Common Subsequence	Medium	Top_100_Liked_Questions, String, Dynamic_Programming, Big_O_Time_O(nm)_Space_O(nm)	33	46.23
0072	Edit Distance	Medium	Top_100_Liked_Questions, String, Dynamic_Programming, Big_O_Time_O(n^2)_Space_O(n2)	4	90.13

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)	17	91.77
0518	Coin Change 2	Medium	Array, Dynamic_Programming	4	84.67

Day 21


0377	Combination Sum IV	Medium	Array, Dynamic_Programming	1	92.54
0343	Integer Break	Medium	Dynamic_Programming, Math	0	100.00
0279	Perfect Squares	Medium	Dynamic_Programming, Math, Breadth_First_Search	1	100.00

Programming Skills I

Day 1 Basic Data Type


1523	Count Odd Numbers in an Interval Range	Easy	Math	0	100.00
1491	Average Salary Excluding the Minimum and Maximum Salary	Easy	Array, Sorting	0	100.00

Day 2 Operator


0191	Number of 1 Bits	Easy	Top_Interview_Questions, Bit_Manipulation	1	84.87
1281	Subtract the Product and Sum of Digits of an Integer	Easy	Math	0	100.00

Day 3 Conditional Statements


0976	Largest Perimeter Triangle	Easy	Array, Math, Sorting, Greedy	12	26.01
1779	Find Nearest Point That Has the Same X or Y Coordinate	Easy	Array	1	100.00

Day 4 Loop


1822	Sign of the Product of an Array	Easy	Array, Math	1	58.05
1502	Can Make Arithmetic Progression From Sequence	Easy	Array, Sorting	2	90.55
0202	Happy Number	Easy	Top_Interview_Questions, Hash_Table, Math, Two_Pointers	1	98.59
1790	Check if One String Swap Can Make Strings Equal	Easy	String, Hash_Table, Counting	0	100.00

Day 5 Function


0589	N-ary Tree Preorder Traversal	Easy	Depth_First_Search, Tree, Stack	1	90.98
0496	Next Greater Element I	Easy	Array, Hash_Table, Stack, Monotonic_Stack	4	81.18
1232	Check If It Is a Straight Line	Easy	Array, Math, Geometry	0	100.00

Day 6 Array


1588	Sum of All Odd Length Subarrays	Easy	Array, Math, Prefix_Sum	0	100.00
0283	Move Zeroes	Easy	Top_100_Liked_Questions, Array, Two_Pointers, Big_O_Time_O(n)_Space_O(1)	2	79.54
1672	Richest Customer Wealth	Easy	Array, Matrix	0	100.00

Day 7 Array


1572	Matrix Diagonal Sum	Easy	Array, Matrix	0	100.00
0566	Reshape the Matrix	Easy	Array, Matrix, Simulation	1	90.08

Day 8 String


1768	Merge Strings Alternately	Easy	String, Two_Pointers	1	86.26
1678	Goal Parser Interpretation	Easy	String	0	100.00
0389	Find the Difference	Easy	String, Hash_Table, Sorting, Bit_Manipulation	1	100.00

Day 9 String


0709	To Lower Case	Easy	String	1	71.74
1309	Decrypt String from Alphabet to Integer Mapping	Easy	String	6	28.25
0953	Verifying an Alien Dictionary	Easy	Array, String, Hash_Table	0	100.00

Day 10 Linked List and Tree


1290	Convert Binary Number in a Linked List to Integer	Easy	Math, Linked_List	0	100.00
0876	Middle of the Linked List	Easy	Two_Pointers, Linked_List	0	100.00
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)	0	100.00
0404	Sum of Left Leaves	Easy	Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree	1	29.26

Day 11 Containers and Libraries


1356	Sort Integers by The Number of 1 Bits	Easy	Array, Sorting, Bit_Manipulation, Counting	10	65.50
0232	Implement Queue using Stacks	Easy	Stack, Design, Queue	1	67.21
0242	Valid Anagram	Easy	String, Hash_Table, Sorting	2	99.01
0217	Contains Duplicate	Easy	Top_Interview_Questions, Array, Hash_Table, Sorting	6	96.68

Day 12 Class and Object


1603	Design Parking System	Easy	Design, Simulation, Counting	8	76.16
0303	Range Sum Query - Immutable	Easy	Array, Design, Prefix_Sum	7	100.00

Programming Skills II

Day 1


0896	Monotonic Array	Easy	Array	2	86.21
0028	Implement strStr()	Easy	Top_Interview_Questions, String, Two_Pointers, String_Matching	0	100.00

Day 2


0110	Balanced Binary Tree	Easy	Depth_First_Search, Tree, Binary_Tree	1	98.82
0459	Repeated Substring Pattern	Easy	String, String_Matching	8	96.64

Day 3


0150	Evaluate Reverse Polish Notation	Medium	Top_Interview_Questions, Array, Math, Stack	9	51.23
0066	Plus One	Easy	Top_Interview_Questions, Array, Math	0	100.00

Day 4


1367	Linked List in Binary Tree	Medium	Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Linked_List	2	61.23
0043	Multiply Strings	Medium	String, Math, Simulation	1	100.00

Day 5


0067	Add Binary	Easy	String, Math, Bit_Manipulation, Simulation	1	100.00
0989	Add to Array-Form of Integer	Easy	Array, Math	7	65.92

Day 6


0739	Daily Temperatures	Medium	Top_100_Liked_Questions, Array, Stack, Monotonic_Stack, Big_O_Time_O(n)_Space_O(n)	10	94.99
0058	Length of Last Word	Easy	String	0	100.00

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)	0	100.00
1886	Determine Whether Matrix Can Be Obtained By Rotation	Easy	Array, Matrix	1	78.38

Day 8


0054	Spiral Matrix	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Array, Matrix, Simulation	0	100.00
0973	K Closest Points to Origin	Medium	Array, Math, Sorting, Heap_Priority_Queue, Divide_and_Conquer, Geometry, Quickselect	4	98.26

Day 9


1630	Arithmetic Subarrays	Medium	Array, Sorting	8	93.62
0429	N-ary Tree Level Order Traversal	Medium	Breadth_First_Search, Tree	3	80.26

Day 10


0503	Next Greater Element II	Medium	Array, Stack, Monotonic_Stack	7	97.03
0556	Next Greater Element III	Medium	String, Math, Two_Pointers	0	100.00

Day 11


1376	Time Needed to Inform All Employees	Medium	Depth_First_Search, Breadth_First_Search, Tree	8	99.85
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)	6	92.28

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)	6	99.03
0713	Subarray Product Less Than K	Medium	Array, Sliding_Window	8	39.00

Day 13


0304	Range Sum Query 2D - Immutable	Medium	Array, Matrix, Design, Prefix_Sum	153	87.51
0910	Smallest Range II	Medium	Array, Math, Sorting, Greedy	10	73.16

Day 14


0143	Reorder List	Medium	Two_Pointers, Stack, Linked_List, Recursion	2	72.59
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)	0	100.00

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))	1	100.00
0445	Add Two Numbers II	Medium	Math, Stack, Linked_List	3	90.38

Day 16


0061	Rotate List	Medium	Two_Pointers, Linked_List	0	100.00
0173	Binary Search Tree Iterator	Medium	Tree, Binary_Tree, Stack, Design, Binary_Search_Tree, Iterator	18	84.18

Day 17


1845	Seat Reservation Manager	Medium	Design, Heap_Priority_Queue	47	87.63
0860	Lemonade Change	Easy	Array, Greedy	2	90.84

Day 18


0155	Min Stack	Medium	Top_100_Liked_Questions, Top_Interview_Questions, Stack, Design, Big_O_Time_O(1)_Space_O(N)	3	100.00
0341	Flatten Nested List Iterator	Medium	Depth_First_Search, Tree, Stack, Design, Queue, Iterator	2	99.95

Day 19


1797	Design Authentication Manager	Medium	Hash_Table, Design	41	92.67
0707	Design Linked List	Medium	Design, Linked_List	10	70.60

Day 20


0380	Insert Delete GetRandom O(1)	Medium	Array, Hash_Table, Math, Design, Randomized	27	93.44
0622	Design Circular Queue	Medium	Array, Design, Linked_List, Queue	3	100.00
0729	My Calendar I	Medium	Binary_Search, Design, Ordered_Set, Segment_Tree	17	97.23

Graph Theory I

Day 1 Matrix Related Problems


0733	Flood Fill	Easy	Array, Depth_First_Search, Breadth_First_Search, Matrix	1	85.36
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(MN)_Space_O(MN)	3	97.76

Day 2 Matrix Related Problems


0695	Max Area of Island	Medium	Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find	3	76.79
1254	Number of Closed Islands	Medium	Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find	3	55.59

Day 3 Matrix Related Problems


1020	Number of Enclaves	Medium	Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find	6	68.24
1905	Count Sub Islands	Medium	Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find	24	85.54

Day 4 Matrix Related Problems


1162	As Far from Land as Possible	Medium	Array, Dynamic_Programming, Breadth_First_Search, Matrix	16	62.40
0417	Pacific Atlantic Water Flow	Medium	Array, Depth_First_Search, Breadth_First_Search, Matrix	5	92.62

Day 5 Matrix Related Problems


1091	Shortest Path in Binary Matrix	Medium	Array, Breadth_First_Search, Matrix	22	69.99
0542	01 Matrix	Medium	Array, Dynamic_Programming, Breadth_First_Search, Matrix	7	95.83

Day 6 Matrix Related Problems


0934	Shortest Bridge	Medium	Array, Depth_First_Search, Breadth_First_Search, Matrix	6	97.87
1926	Nearest Exit from Entrance in Maze	Medium	Array, Breadth_First_Search, Matrix	12	40.55

Day 7 Standard Traversal


0797	All Paths From Source to Target	Medium	Depth_First_Search, Breadth_First_Search, Graph, Backtracking	2	90.53
0841	Keys and Rooms	Medium	Depth_First_Search, Breadth_First_Search, Graph	3	51.54

Day 8 Standard Traversal


0547	Number of Provinces	Medium	Depth_First_Search, Breadth_First_Search, Graph, Union_Find	2	69.51
1319	Number of Operations to Make Network Connected	Medium	Depth_First_Search, Breadth_First_Search, Graph, Union_Find	9	67.64

Day 9 Standard Traversal


1376	Time Needed to Inform All Employees	Medium	Depth_First_Search, Breadth_First_Search, Tree	8	99.85
0802	Find Eventual Safe States	Medium	Depth_First_Search, Breadth_First_Search, Graph, Topological_Sort	7	74.93

Day 10 Standard Traversal


1129	Shortest Path with Alternating Colors	Medium	Breadth_First_Search, Graph	4	96.63
1466	Reorder Routes to Make All Paths Lead to the City Zero	Medium	Depth_First_Search, Breadth_First_Search, Graph	39	97.71
0847	Shortest Path Visiting All Nodes	Hard	Dynamic_Programming, Breadth_First_Search, Bit_Manipulation, Graph, Bitmask	14	78.72

Day 11 Breadth First Search


1306	Jump Game III	Medium	Array, Depth_First_Search, Breadth_First_Search	2	96.23
1654	Minimum Jumps to Reach Home	Medium	Array, Dynamic_Programming, Breadth_First_Search	6	99.87
0365	Water and Jug Problem	Medium	Math, Depth_First_Search, Breadth_First_Search	0	100.00

Day 12 Breadth First Search


0433	Minimum Genetic Mutation	Medium	String, Hash_Table, Breadth_First_Search	1	90.95
0752	Open the Lock	Medium	Array, String, Hash_Table, Breadth_First_Search	72	91.06
0127	Word Ladder	Hard	Top_Interview_Questions, String, Hash_Table, Breadth_First_Search	37	94.58

Day 13 Graph Theory


0997	Find the Town Judge	Easy	Array, Hash_Table, Graph	3	80.64
1557	Minimum Number of Vertices to Reach All Nodes	Medium	Graph	8	99.94

Day 14 Graph Theory


1615	Maximal Network Rank	Medium	Graph	3	97.34
0886	Possible Bipartition	Medium	Depth_First_Search, Breadth_First_Search, Graph, Union_Find	20	80.12
0785	Is Graph Bipartite?	Medium	Depth_First_Search, Breadth_First_Search, Graph, Union_Find	0	100.00

SQL I

Day 1 Select


0595	Big Countries	Easy	Database	262	84.64
1757	Recyclable and Low Fat Products	Easy	Database	475	71.54
0584	Find Customer Referee	Easy	Database	531	58.63
0183	Customers Who Never Order	Easy	Database	376	98.73

Day 2 Select and Order


1873	Calculate Special Bonus	Easy	Database	543	71.60
0627	Swap Salary	Easy	Database	191	96.89
0196	Delete Duplicate Emails	Easy	Database	903	48.10

Day 3 String Processing Functions


1667	Fix Names in a Table	Easy	Database	559	80.29
1484	Group Sold Products By The Date	Easy	LeetCode_Curated_SQL_70, Database	395	77.20
1527	Patients With a Condition	Easy	Database	308	66.93

Day 4 Union and Select


1965	Employees With Missing Information	Easy	Database	617	30.40
1795	Rearrange Products Table	Easy	Database	497	64.83
0608	Tree Node	Medium	LeetCode_Curated_SQL_70, Database	347	95.17
0176	Second Highest Salary	Medium	Database	225	73.10

Day 5 Union


0175	Combine Two Tables	Easy	Database	491	32.30
1581	Customer Who Visited but Did Not Make Any Transactions	Easy	Database	1039	76.99
1148	Article Views I	Easy	LeetCode_Curated_SQL_70, Database	783	64.09

Day 6 Union


0197	Rising Temperature	Easy	Database	342	93.76
0607	Sales Person	Easy	LeetCode_Curated_SQL_70, Database	1046	86.04

Day 7 Function


1141	User Activity for the Past 30 Days I	Easy	LeetCode_Curated_SQL_70, Database	849	72.54
1693	Daily Leads and Partners	Easy	Database	463	78.98
1729	Find Followers Count	Easy	Database	456	88.39

Day 8 Function


0586	Customer Placing the Largest Number of Orders	Easy	LeetCode_Curated_SQL_70, Database	484	66.42
0511	Game Play Analysis I	Easy	LeetCode_Curated_SQL_70, Database	586	56.94
1890	The Latest Login in 2020	Easy	Database	571	73.59
1741	Find Total Time Spent by Each Employee	Easy	Database	414	93.27

Day 9 Control of Flow


1393	Capital Gain/Loss	Medium	LeetCode_Curated_SQL_70, Database	428	92.01
1407	Top Travellers	Easy	LeetCode_Curated_SQL_70, Database	682	70.16
1158	Market Analysis I	Medium	Database	2511	78.92

Day 10 Where


0182	Duplicate Emails	Easy	Database	303	92.08
1050	Actors and Directors Who Cooperated At Least Three Times	Easy	LeetCode_Curated_SQL_70, Database	344	76.48
1587	Bank Account Summary II	Easy	Database	630	60.32
1084	Sales Analysis III	Easy	LeetCode_Curated_SQL_70, Database	1066	69.71

Contributing

Your ideas/fixes/algorithms are more than welcome!

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

License

jabOsmond/LeetCode-in-Java

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