LeetCode Solutions

Recurions + BackTracking

#	Title	Difficulty	Complexity	Solution
131	Palindrome Partitioning	Time - O(n) Space - O(1)	Medium	Java
17	Letter Combinations of a Phone Number	Time - O(n) Space - O(1)	Medium	Java
55	Jump Game - Without DP	Time - O(n) Space - O(1)	Medium	Java
51	N-Queens	Time - O(n) Space - O(1)	Hard	Java
52	N-QueensII	Time - O(n) Space - O(1)	Hard	Java
37	Sudoku Solver	Time - O(n) Space - O(1)	Hard	Java
46	Permutations	Time - O(n) Space - O(1)	Medium	Java
47	Permutations II	Time - O(n) Space - O(1)	Medium	Java
77	Combinations	Time - O(n) Space - O(1)	Medium	Java
39	CombinationSum	Time - O(n) Space - O(1)	Medium	Java
40	Combination Sum II	Time - O(n) Space - O(1)	Medium	Java
216	Combination Sum III	Time - O(n) Space - O(1)	Medium	Java
139	Word Break Without DP	Time - O(n) Space - O(1)	Medium	Java
79	Word Search	Time - O(n) Space - O(1)	Medium	Java
78	Subsets	Time - O(n) Space - O(1)	Medium	Java
90	Subsets II	Time - O(n) Space - O(1)	Medium	Java

Dynamic Programming

#	Title	Difficulty	Complexity	Solution
198	House Robber	Time - O(n) Space - O(1)	Medium	Java
518	Coin Change II	Time - O(n) Space - O(1)	Medium	Java
115	Distinct Subsequences	Time - O(n) Space - O(1)	Hard	Java
1143	Longest Common Subsequence	Time - O(n) Space - O(1)	Medium	Java
1035	Uncrossed Lines	Time - O(n) Space - O(1)	Medium	Java
72	Edit Distance	Time - O(n) Space - O(1)	Hard	Java
300	Longest Increasing Subsequence	Time - O(n) Space - O(1)	Medium	Java

Map

#	Title	Difficulty	Complexity	Solution
350	Intersection of Two Arrays II	Time - O(n) Space - O(1)	Easy	Java
49	Group Anagrams	Time - O(n) Space - O(1)	Medium	Java
128	Longest Consecutive Sequence	Time - O(n) Space - O(1)	Medium	Java

Strings

#	Title	Difficulty	Complexity	Solution
647	Palindromic Substrings		Medium	Java

Heap

#	Title	Difficulty	Complexity	Solution
215	Kth Largest Element in an Array	Time - O(n) Space - O(1)	Medium	Java

Tree/BST

#	Title	Difficulty	Complexity	Solution
101	Symmetric Tree	Time - O(n) Space - O(1)	Easy	Java
951	Flip Equivalent Binary Trees	Time - O(n) Space - O(1)	Medium	Java
112	Path Sum	Time - O(n) Space - O(1)	Easy	Java
543	Diameter of Binary Tree	Time - O(n) Space - O(1)	Easy	Java
701	Insert into a Binary Search Tree	Time - O(n) Space - O(1)	Medium	Java
110	Balanced Binary Tree	Time - O(n) Space - O(1)	Easy	Java
98	Validate Binary Search Tree	Time - O(n) Space - O(1)	Medium	Java
450	Delete Node in a BST	Time - O(n) Space - O(1)	Medium	Java
236	Lowest Common Ancestor of a Binary Tree	Time - O(n) Space - O(1)	Medium	Java
105	Construct Binary Tree from Preorder and Inorder Traversal	Time - O(n) Space - O(1)	Medium	Java

Sliding Window

#	Title	Difficulty	Complexity	Solution
239	Sliding Window Maximum	Time - O(n) Space - O(1)	Hard	Java
209	Minimum Size Subarray Sum	Time - O(n) Space - O(1)	Medium	Java
904	Fruits Into Basket	Time - O(n) Space - O(1)	Medium	Java
1358	Number of Substrings Containing All Three Characters	Time - O(n) Space - O(1)	Medium	Java
424	Longest Repeating Character Replacement	Time - O(n) Space - O(1)	Medium	Java
930	Binary Subarrays With Sum	Time - O(n) Space - O(1)	Medium	Java
1248	Count Number of Nice Subarrays	Time - O(n) Space - O(1)	Medium	Java
1234	Replace the Substring for Balanced String	Time - O(n) Space - O(1)	Medium	Java
1004	Max Consecutive Ones III	Time - O(n) Space - O(1)	Medium	Java
1208	Get Equal Substrings Within Budget	Time - O(n) Space - O(1)	Medium	Java
30	Substring with Concatenation of All Words	Time - O(n) Space - O(1)	Hard	Java

Arrays

#	Title	Difficulty	Complexity	Solution
1	Two Sum	Time - O(n) Space - O(1)	Easy	Java
23	Remove Duplicates from Sorted Array	Time - O(n) Space - O(1)	Easy	Java
1769	Minimum Number of Operations to Move All Balls to Each Box	Time - O(n) Space - O(1)	Medium	Java
189	Rotate Array	Time - O(n) Space - O(1)	Medium	Java
238	Product of Array Except Self	Time - O(n) Space - O(1)	Medium	Java
42	Trapping Rain Water	Time - O(n) Space - O(n)	Hard	Java
53	Maximum Subarray	Time - O(n) Space - O(1)	Easy	Java
134	Gas Station	Time - O(n) Space - O(1)	Medium	Java
349	Intersection of Two Arrays	Time - O(n) Space - O(1)	Easy	Java
88	Merge Sorted Array	Time - O(n) Space - O(1)	Easy	Java
26	Remove Duplicates from Sorted Array	Time - O(n) Space - O(1)	Easy	Java
169	Majority Element	Time - O(n) Space - O(1)	Easy	Java
268	Missing Number	Time - O(n) Space - O(1)	Easy	Java
217	Contains Duplicate	Time - O(n) Space - O(1)	Easy	Java
283	Move Zeroes	Time - O(n) Space - O(1)	Easy	Java
287	Find the Duplicate Number	Time - O(n) Space - O(1)	Medium	Java

2 Pointers

#	Title	Difficulty	Complexity	Solution
167	Two Sum II - Input Array Is Sorted	Time - O(n) Space - O(1)	Medium	Java
15	3Sum	Time - O(n2) Space - O(1)	Medium	Java
844	Backspace String Compare	Time - O(n) Space - O(n)	Easy	Java

Binary Search

#	Title	Difficulty	Complexity	Solution
278	First Bad Version	Time - O(log(n)) Space - O(1)	Easy	Java
240	Search a 2D Matrix II	Time - O(log(n)) Space - O(1)	Medium	Java
35	Search Insert Position	Time - O(log(n)) Space - O(1)	Easy	Java
69	Sqrt(x)	Time - O(log(n)) Space - O(1)	Easy	Java

Grokking Interview Pattern Solutions

Sliding Window

#	Title	Difficulty	Complexity	Solution
239	Longest Substring with maximum K Distinct Characters	Time - O(n) Space - O(1)	Medium	Java