LeetCode Solutions

This repository contains my leetcode solutions to select questions.

Contents

• Algomap.io
  • Arrays & Strings
  • HashMaps & Sets
  • 2 Pointers
  • Stacks
  • Linked Lists
  • Binary Search
  • Sliding Window
  • Trees
  • Heaps
  • Recursive Backtracking
  • Graphs
  • Dynamic Programming
  • Bit Manipulation

Algomap.io

https://algomap.io/list/

Arrays & Strings

Problem	Solutions	Time	Space
2239. Find Closest Number to Zero	Link	$$O(n)$$	$$O(1)$$
1768. Merge Strings Alternately	Link	$$O(n)$$	$$O(n)$$
13. Roman to Integer	Link	$$O(n)$$	$$O(1)$$
392. Is Subsequence	Link	$$O(n)$$	$$O(1)$$
121. Best Time to Buy and Sell Stock	Link	$$O(n)$$	$$O(1)$$
14. Longest Common Prefix	Link	$$O(n \cdot m)$$	$$O(1)$$
228. Summary Ranges	Link	$$O(n)$$	$$O(1)$$
228. Summary Ranges	Link	$$O(n)$$	$$O(1)$$
26. Remove Duplicates from Sorted Array	Link	$$O(n)$$	$$O(1)$$
27. Remove Element	Link	$$O(n)$$	$$O(1)$$
88. Merge Sorted Array	Link	$$O(n + m)$$	$$O(1)$$
122. Best Time to Buy and Sell Stock II	Link	$$O(n)$$	$$O(1)$$
80. Remove Duplicates from Sorted Array II	Link	$$O(n)$$	$$O(1)$$
75. Sort Colors (Dutch National Flag Problem)	Link	$$O(n)$$	$$O(1)$$
238. Product of Array Except Self	Link	$$O(n)$$	$$O(1)$$
274. H-Index	Link	$$O(n)$$	$$O(n)$$
56. Merge Intervals	Link	$$O(n \cdot \log n)$$	$$O(n)$$
54. Spiral Matrix	Link	$$O(m \cdot n)$$	$$O(1)$$
6. Zigzag Conversion	Link	$$O(n)$$	$$O(n)$$
48. Rotate Image	Link	$$O(n^2)$$	$$O(1)$$

Hashmaps & Sets

Problem	Solutions	Time	Space
771. Jewels and Stones	Link	$$O(n)$$	$$O(n)$$
217. Contains Duplicate	Link	$$O(n)$$	$$O(n)$$
383. Ransom Note	Link	$$O(n + m)$$	$$O(m)$$
242. Valid Anagram	Link	$$O(n)$$	$$O(1)$$
1189. Maximum Number of Balloons	Link	$$O(n)$$	$$O(1)$$
1. Two Sum	Link	$$O(n)$$	$$O(n)$$
36. Valid Sudoku	Link	$$O(1)$$	$$O(1)$$
49. Group Anagrams	Link	$$O(n \cdot m)$$	$$O(n \cdot m)$$
169. Majority Element	Link	$$O(n)$$	$$O(1)$$
128. Longest Consecutive Sequence	Link	$$O(n)$$	$$O(n)$$

2 Pointers

Problem	Solutions	Time	Space
977. Squares of a Sorted Array	Link	$$O(n)$$	$$O(n)$$
344. Reverse String	Link	$$O(n)$$	$$O(1)$$
167. Two Sum II - Input Array Is Sorted	Link	$$O(n)$$	$$O(1)$$
125. Valid Palindrome	Link	$$O(n)$$	$$O(1)$$
15. 3Sum	Link	$$O(n^2)$$	$$O(1)$$
11. Container With Most Water	Link	$$O(n)$$	$$O(1)$$
16. 3Sum Closest	Link	$$O(n^2)$$	$$O(1)$$
18. 4Sum	Link	$$O(n^3)$$	$$O(1)$$

Stacks

Problem	Solutions	Time	Space
682. Baseball Game	Link	$$O(n)$$	$$O(n)$$
20. Valid Parentheses	Link	$$O(n)$$	$$O(n)$$
150. Evaluate Reverse Polish Notation	Link	$$O(n)$$	$$O(n)$$
739. Daily Temperatures	Link	$$O(n)$$	$$O(n)$$
155. Min Stack	Link	$$O(1)$$	$$O(n)$$

Linked Lists

Problem	Solutions	Time	Space
83. Remove Duplicates from Sorted List	Link	$$O(n)$$	$$O(1)$$
2807. Insert Greatest Common Divisors in Linked List	Link	$$O(n)$$	$$O(1)$$
206. Reverse Linked List	Link	$$O(n)$$	$$O(1)$$
21. Merge Two Sorted Lists	Link	$$O(n + m)$$	$$O(1)$$
141. Linked List Cycle	Link	$$O(n)$$	$$O(1)$$
876. Middle of the Linked List	Link	$$O(n)$$	$$O(1)$$
19. Remove Nth Node From End of List	Link	$$O(n)$$	$$O(1)$$
138. Copy List with Random Pointer	Link	$$O(n)$$	$$O(n)$$

Binary Search

Problem	Solutions	Time	Space
704. Binary Search	Link	$$O(\log n)$$	$$O(1)$$
35. Search Insert Position	Link	$$O(\log n)$$	$$O(1)$$
278. First Bad Version	Link	$$O(\log n)$$	$$O(1)$$
367. Valid Perfect Square	Link	$$O(\log n)$$	$$O(1)$$
74. Search a 2D Matrix	Link	$$O(\log (m \cdot n))$$	$$O(1)$$
153. Find Minimum in Rotated Sorted Array	Link	$$O(\log n)$$	$$O(1)$$
33. Search in Rotated Sorted Array	Link	$$O(\log n)$$	$$O(1)$$
875. Koko Eating Bananas	Link	$$O(n \cdot \log m)$$	$$O(1)$$

Sliding Window

Problem	Solutions	Time	Space
643. Maximum Average Subarray I	Link	$$O(n)$$	$$O(1)$$
1004. Max Consecutive Ones III	Link	$$O(n)$$	$$O(1)$$
3. Longest Substring Without Repeating Characters	Link	$$O(n)$$	$$O(1)$$
424. Longest Repeating Character Replacement	Link	$$O(n)$$	$$O(1)$$
209. Minimum Size Subarray Sum	Link	$$O(n)$$	$$O(1)$$
567. Permutation in String	Link	$$O(n)$$	$$O(1)$$

Trees

Problem	Solutions	Time	Space
226. Invert Binary Tree	Link	$$O(n)$$	$$O(h)$$
104. Maximum Depth of Binary Tree	Link	$$O(n)$$	$$O(h)$$
110. Balanced Binary Tree	Link	$$O(n)$$	$$O(h)$$
543. Diameter of Binary Tree	Link	$$O(n)$$	$$O(h)$$
100. Same Tree	Link	$$O(n)$$	$$O(h)$$
101. Symmetric Tree	Link	$$O(n)$$	$$O(h)$$
112. Path Sum	Link	$$O(n)$$	$$O(h)$$
572. Subtree of Another Tree	Link	$$O(n \cdot m)$$	$$O(h)$$
102. Binary Tree Level Order Traversal (BFS)	Link	$$O(n)$$	$$O(n)$$
637. Average of Levels in Binary Tree	Link	$$O(n)$$	$$O(n)$$
230. Kth Smallest Element in a BST	Link	$$O(n)$$	$$O(h)$$
530. Minimum Absolute Difference in BST	Link	$$O(n)$$	$$O(n)$$
98. Validate Binary Search Tree	Link	$$O(n)$$	$$O(n)$$
235. Lowest Common Ancestor of a Binary Search Tree	Link	$$O(\log n)$$	$$O(1)$$
208. Implement Trie (Prefix Tree)	Link	$$O(m)$$	$$O(n)$$

Heaps

Note: No JavaScript

Problem	Solutions	Time	Space
1046. Last Stone Weight	Link	$$O(n \cdot \log n)$$	$$O(n)$$
215. Kth Largest Element in an Array	Link	$$O(n \cdot \log k)$$	$$O(k)$$
347. Top K Frequent Elements	Link	$$O(n \cdot \log k)$$	$$O(k)$$
973. K Closest Points to Origin	Link	$$O(n \cdot \log k)$$	$$O(k)$$

Recursive Backtracking

Problem	Solutions	Time	Space
78. Subsets	Link	$$O(2^n \cdot n)$$	$$O(2^n \cdot n)$$
46. Permutations	Link	$$O(n \cdot n!)$$	$$O(n \cdot n!)$$
77. Combinations	Link	$$O(C(n, k) \cdot k)$$	$$O(C(n, k) \cdot k)$$
39. Combination Sum	Link	$$O(2^{\frac{t}{m} + 1})$$	$$O(\frac{t}{m})$$
17. Letter Combinations of a Phone Number	Link	$$O(n \cdot 4^n)$$	$$O(n)$$
22. Generate Parentheses	Link	$$O(2^n)$$	$$O(n)$$
45. Jump Game II	Link	$$O(n)$$	$$O(1)$$
79. Word Search	Link	$$O(m \cdot n \cdot 3^w)$$	$$O(w)$$

Graphs

Problem	Solutions	Time	Space
1971. Find if Path Exists in Graph	Link	$$O(V + E)$$	$$O(V + E)$$
200. Number of Islands	Link	$$O(m\cdot n)$$	$$O(m\cdot n)$$
695. Max Area of Island	Link	$$O(m\cdot n)$$	$$O(m\cdot n)$$
207. Course Schedule (Detect Cycles in a Graph)	Link	$$O(V + E)$$	$$O(V + E)$$

Dynamic Programming

Bit Manipulation