Disclaimer

	Most of the problems are solved by using the Algo library.
	Solutions to HackerRank problems.
	Solutions to InterviewBit problems.

The problem solutions and implementations are entirely provided by Alex Prut. The code is not refactored, no coding style is followed, the only purpose of the written code is to pass all the platform tests of a given problem.

Problems

Number	Title	Difficulty	Solution
1	Two Sum	Easy	Solution.java
2	Add Two Numbers	Medium	Solution.java
3	Longest Substring Without Repeating Characters	Medium	Solution.java
11	Container With Most Water	Medium	Solution.java
14	Longest Common Prefix	Easy	Solution.java
20	Valid Parentheses	Easy	Solution.java
21	Merge Two Sorted Lists	Easy	Solution.java
23	Merge k Sorted Lists	Hard	Solution.java
27	Remove Element	Easy	Solution.java
34	Find First and Last Position of Element in Sorted Array	Medium	Solution.java
39	Combination Sum	Medium	Solution.java
46	Permutations	Medium	Solution.java
47	Permutations II	Medium	Solution.java
49	Group Anagrams	Medium	Solution.java
53	Maximum Subarray	Medium	Solution.java
56	Merge Intervals	Medium	Solution.java
61	Rotate List	Medium	Solution.java
62	Unique Paths](https://leetcode.com/problems/unique-paths/)	Medium	Solution.java
64	Minimum Path Sum](https://leetcode.com/problems/minimum-path-sum/)	Medium	Solution.java
70	Climbing Stairs	Easy	Solution.java
72	Edit Distance	Medium	Solution.java
73	Set Matrix Zeroes	Medium	Solution.java
77	Combinations	Medium	Solution.java
88	Merge Sorted Array	Easy	Solution.java
92	Reverse Linked List II	Medium	Solution.java
94	Binary Tree Inorder Traversal	Medium	Solution.java
98	Validate Binary Search Tree	Medium	Solution.java
100	Same Tree	Easy	Solution.java
102	Binary Tree Level Order Traversal	Medium	Solution.java
103	Binary Tree Zigzag Level Order Traversal	Medium	Solution.java
104	Maximum Depth of Binary Tree	Easy	Solution.java
108	Convert Sorted Array to Binary Search Tree	Easy	Solution.java
111	Minimum Depth of Binary Tree	Easy	Solution.java
114	Flatten Binary Tree to Linked List	Medium	Solution.java
115	Min Stack	Medium	Solution.java
129	Sum Root to Leaf Numbers	Medium	Solution.java
130	Surrounded Regions	Medium	Solution.java
133	Clone Graph	Medium	Solution.java
136	Single Number	Easy	Solution.java
139	Word Break	Medium	Solution.java
146	LRU Cache	Medium	Solution.java
151	Reverse Words in a String	Medium	Solution.java
162	Find Peak Element	Medium	Solution.java
167	Two Sum II - Input Array Is Sorted	Medium	Solution.java
173	Binary Search Tree Iterator	Medium	Solution.java
189	Rotate Array	Medium	Solution.java
190	Reverse Bits	Easy	Solution.java
200	Number of Islands	Medium	Solution.java
211	Design Add and Search Words Data Structure	Medium	Solution.java
206	Reverse Linked List	Easy	Solution.java
208	Implement Trie (Prefix Tree)	Medium	Solution.java
209	Minimum Size Subarray Sum	Medium	Solution.java
225	Implement Stack using Queues	Easy	Solution.java
230	Kth Smallest Element in a BST	Medium	Solution.java
232	Implement Queue using Stacks	Easy	Solution.java
235	Implement Stack using Queues	Easy	Solution.java
236	Lowest Common Ancestor of a Binary Tree	Medium	Solution.java
237	Delete Node in a Linked List	Easy	Solution.java
240	Search a 2D Matrix II	Medium	Solution.java
274	H-Index	Medium	Solution.java
300	Longest Increasing Subsequence	Medium	Solution.java
344	Reverse String	Easy	Solution.java
412	Fizz Buzz	Easy	Solution.java
433	Minimum Genetic Mutation	Medium	Solution.java
451	Sort Characters By Frequency	Medium	Solution.java
460	LFU Cache	Hard	Solution.java
535	Encode and Decode TinyURL	Medium	Solution.java
538	Convert BST to Greater Tree	Medium	Solution.java
559	Maximum Depth of N-ary Tree	Easy	Solution.java
566	Reshape the Matrix	Easy	Solution.java
567	Permutation in String	Medium	Solution.java
589	N-ary Tree Preorder Traversal	Easy	Solution.java
590	N-ary Tree Postorder Traversal	Easy	Solution.java
595	Big Countries	Easy	Solution.java
620	Not Boring Movies	Easy	Solution.txt
617	Merge Two Binary Trees	Easy	Solution.java
695	Max Area of Island	Medium	Solution.java
700	Search in a Binary Search Tree	Easy	Solution.java
701	Insert into a Binary Search Tree	Medium	Solution.java
705	Design HashSet	Easy	Solution.java
706	Design HashMap	Easy	Solution.java
707	Design Linked List	Medium	Solution.java
709	To Lower Case	Easy	Solution.java
763	Partition Labels	Medium	Solution.java
771	Jewels and Stones	Easy	Solution.java
784	Letter Case Permutation	Medium	Solution.java
797	All Paths From Source to Target	Medium	Solution.java
804	Unique Morse Code Words	Easy	Solution.java
814	Binary Tree Pruning	Medium	Solution.java
832	Flipping an Image	Easy	Solution.java
867	Transpose Matrix	Easy	Solution.java
938	Range Sum of BST	Easy	Solution.java
946	Validate Stack Sequences	Medium	Solution.java
950	Reveal Cards In Increasing Order	Medium	Solution.java
965	Univalued Binary Tree	Easy	Solution.java
1008	Construct Binary Search Tree from Preorder Traversal	Medium	Solution.java
1021	Remove Outermost Parentheses	Easy	Solution.java
1038	Binary Search Tree to Greater Sum Tree	Medium	Solution.java
1091	Shortest Path in Binary Matrix	Medium	Solution.java
1108	Defanging an IP Address	Easy	Solution.java
1137	N-th Tribonacci Number	Easy	Solution.java
1143	Longest Common Subsequence	Medium	Solution.java
1179	Reformat Department Table	Easy	Solution.java
1206	Design Skiplist	Hard	Solution.java
1221	Split a String in Balanced Strings	Easy	Solution.java
1252	Cells with Odd Values in a Matrix	Easy	Solution.java
1266	Minimum Time Visiting All Points	Easy	Solution.java
1268	Search Suggestions System	Medium	Solution.java
1281	Subtract the Product and Sum of Digits of an Integer	Easy	Solution.java
1282	Group the People Given the Group Size They Belong To	Medium	Solution.java
1290	Convert Binary Number in a Linked List to Integer	Easy	Solution.java
1295	Find Numbers with Even Number of Digits	Easy	Solution.java
1299	Replace Elements with Greatest Element on Right Side	Easy	Solution.java
1302	Deepest Leaves Sum	Medium	Solution.java
1304	Find N Unique Integers Sum up to Zero	Easy	Solution.java
1305	All Elements in Two Binary Search Trees	Medium	Solution.java
1309	Decrypt String from Alphabet to Integer Mapping	Easy	Solution.java
1313	Decompress Run-Length Encoded List	Easy	Solution.java
1315	Sum of Nodes with Even-Valued Grandparent	Medium	Solution.java
1323	Maximum 69 Number	Easy	Solution.java
1329	Sort the Matrix Diagonally	Medium	Solution.java
1337	The K Weakest Rows in a Matrix	Easy	Solution.java
1342	Number of Steps to Reduce a Number to Zero	Easy	Solution.java
1347	Minimum Number of Steps to Make Two Strings Anagram	Medium	Solution.java
1351	Count Negative Numbers in a Sorted Matrix	Easy	Solution.java
1365	How Many Numbers Are Smaller Than the Current Number	Easy	Solution.java
1370	Increasing Decreasing String	Easy	Solution.java
1374	Generate a String With Characters That Have Odd Counts	Easy	Solution.java
1379	Find a Corresponding Node of a Binary Tree in a Clone of That Tree	Medium	Solution.java
1380	Lucky Numbers in a Matrix	Easy	Solution.java
1382	Balance a Binary Search Tree	Medium	Solution.java
1389	Create Target Array in the Given Order	Easy	Solution.java
1395	Count Number of Teams	Medium	Solution.java
1408	String Matching in an Array	Easy	Solution.java
1409	Queries on a Permutation With Key	Medium	Solution.java
1447	Simplified Fractions	Medium	Solution.java
1450	Number of Students Doing Homework at a Given Time	Easy	Solution.java
1464	Maximum Product of Two Elements in an Array	Easy	Solution.java
1470	Shuffle the Array	Easy	Solution.java
1480	Running Sum of 1d Array	Easy	Solution.java
1512	Number of Good Pairs	Easy	Solution.java
1534	Count Good Triplets	Easy	Solution.java
1557	Minimum Number of Vertices to Reach All Nodes	Medium	Solution.java
1588	Sum of All Odd Length Subarrays	Easy	Solution.java
1603	Design Parking System	Easy	Solution.java
1605	Find Valid Matrix Given Row and Column Sums	Medium	Solution.java
1684	Count the Number of Consistent Strings	Easy	Solution.java
1700	Number of Students Unable to Eat Lunch	Easy	Solution.java
1742	Maximum Number of Balls in a Box	Easy	Solution.java
1784	Check if Binary String Has at Most One Segment of Ones	Easy	Solution.java
1791	Find Center of Star Graph	Easy	Solution.java
1817	Finding the Users Active Minutes	Medium	Solution.java
1829	Maximum XOR for Each Query	Medium	Solution.java
1971	Find if Path Exists in Graph	Easy	Solution.java
2102	Sequentially Ordinal Rank Tracker	Hard	Solution.java
2130	Maximum Twin Sum of a Linked List	Medium	Solution.java
2181	Merge Nodes in Between Zeros	Medium	Solution.java
2315	Count Asterisks	Easy	Solution.java
2336	Smallest Number in Infinite Set	Medium	Solution.java
2363	Merge Similar Items	Easy	Solution.java
2427	Number of Common Factors	Easy	Solution.java
2485	Find the Pivot Integer	Easy	Solution.java
2545	Sort the Students by Their Kth Score	Medium	Solution.java

License

Licensed under MIT.