My LeetCode Solutions

Problems

• 1. Two Sum

  • Easy
  • Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 3.4 MB, less than 46.15%
  • v3 solution
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 3.3 MB, less than 53.85%

• 9. Palindrome Number

  • Easy
  • Completely Solved
    • Runtime: 4 ms, faster than 99.27%
    • Memory Usage: 5 MB, less than 100.00%

• 12. Integer to Roman

  • Medium
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 3.3 MB, less than 100.00%

• 13. Roman to Integer

  • Easy
  • Completely Solved
    • Runtime: 4 ms, faster than 91.56%
    • Memory Usage: 3 MB, less than 85.71%

• 20. Valid Parentheses

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2 MB, less than 100.00%

• 33. Search in Rotated Sorted Array

  • Medium
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2.6 MB, less than 50.00% (This must be the best score)

• 35. Search Insert Position

  • Easy
  • Completely Solved
    • Runtime: 4 ms, faster than 86.34%
    • Memory Usage: 3.1 MB, less than 100.00%

• 41. First Missing Positive

  • Hard
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2.2 MB, less than 100.00%

• 53. Maximum Subarray

  • Easy
  • Completely Solved
    • Runtime: 4 ms, faster than 97.20%
    • Memory Usage: 3.3 MB, less than 100.00%

• 72. Edit Distance

  • Hard
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2.7 MB, less than 100.00%

• 75. Sort Colors

  • Medium
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2 MB, less than 98.96%

• 96. Unique Binary Search Trees

  • Medium
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 1.9 MB, less than 91.07%

• 100. Same Tree

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2.1 MB, less than 100.00%

• 107. Binary Tree Level Order Traversal II

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 3 MB, less than 43.48%
      • Efficient enough as DFS solution, less memory usage solutions are using BFS

• 111. Minimum Depth of Binary Tree

  • Easy
  • Completely Solved
    • Runtime: 4 ms, faster than 96.23%
    • Memory Usage: 5.2 MB, less than 100.00%

• 113. Path Sum II

  • Medium
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 4.6 MB, less than 100.00%

• 118. Pascal's Triangle

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2.3 MB, less than 100.00%

• 119. Pascal's Triangle II

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2 MB, less than 100.00%

• 121. Best Time to Buy and Sell Stock

  • Easy
  • Completely Solved
    • Runtime: 4 ms, faster than 96.24%
    • Memory Usage: 3.1 MB, less than 100.00%

• 122. Best Time to Buy and Sell Stock II

  • Easy
  • Completely Solved
    • Runtime: 4 ms, faster than 97.35%
    • Memory Usage: 3.1 MB, less than 100.00%

• 129. Sum Root to Leaf Numbers

  • Medium
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2.4 MB, less than 100.00%

• 136. Single Number

  • Easy
  • Solved
    • Runtime: 8 ms, faster than 92.78%
    • Memory Usage: 4.7 MB, less than 100.00%

• 139. Word Break

  • Medium
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2.1 MB, less than 100.00%

• 140. Word Break II

  • Hard
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2.6 MB, less than 100.00%

• 142. Linked List Cycle II

• 167. Two Sum II - Input array is sorted

  • Easy
  • Completely Solved
    • Runtime: 4 ms, faster than 95.05%
    • Memory Usage: 3 MB, less than 100.00%

• 168. Excel Sheet Column Title

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2 MB, less than 100.00%

• 181. Employees Earning More Than Their Managers

  • Easy
  • Completely Solved
    • Runtime: 316 ms, faster than 94.84%
    • Memory Usage: 0B, less than 100.00%

• 191. Number of 1 Bits

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2 MB, less than 100.00%

• 198. House Robber

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2 MB, less than 100.00%

• 201. Bitwise AND of Numbers Range

  • Easy
  • Completely Solved
    • Runtime: 8 ms, faster than 96.30%
    • Memory Usage: 6.1 MB, less than 100.00%

• 202. Happy Number

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2 MB, less than 100.00%

• 207. Course Schedule

  • Medium
  • Completely Solved
    • Runtime: 8 ms, faster than 98.08%
    • Memory Usage: 5.9 MB, less than 100.00%

• 222. Count Complete Tree Nodes

  • Medium
  • Completely Solved
    • Runtime: 12 ms, faster than 99.55%
    • Memory Usage: 6.5 MB, less than 86.90%

• 231. Power of Two

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2.2 MB, less than 100.00%

• 236. Lowest Common Ancestor of a Binary Tree

  • Easy
  • Completely Solved
    • Runtime: 8 ms, faster than 99.49%
    • Memory Usage: 7.3 MB, less than 100.00%

• 274. H-Index

  • Medium
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2.3 MB, less than 100.00%

• 275. H-Index II

  • Medium
  • Completely Solved
    • Runtime: 16 ms, faster than 91.67%
    • Memory Usage: 6.3 MB, less than 80.00%

• 278. First Bad Version

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2 MB, less than 100.00%

• 283. Move Zeroes

  • Easy
  • Completely Solved
    • Runtime: 4 ms, faster than 93.20%
    • Memory Usage: 3.8 MB, less than 100.00%

• 287. Find the Duplicate Number

  • Medium
  • Completely Solved
    • Runtime: 4 ms, faster than 98.80%
    • Memory Usage: 3.8 MB, less than 100.00%

• 292. Nim Game

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 1.9 MB, less than 100.00%

• 303. Range Sum Query - Immutable

  • Easy
  • Completely Solved
    • Runtime: 28 ms, faster than 97.30%
    • Memory Usage: 8.3 MB, less than 100.00%

• 328. Odd Even Linked List

  • Medium
  • Completely Solved
    • Runtime: 4 ms, faster than 90.59%
    • Memory Usage: 3.3 MB, less than 100.00%

• 338. Counting Bits

  • Medium
  • Completely Solved
    • Runtime: 4 ms, faster than 96.18%
    • Memory Usage: 4.4 MB, less than 100.00%

• 367. Valid Perfect Square

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 1.9 MB, less than 100.00%

• 383. Ransom Note

  • Easy
  • Completely Solved
    • Runtime: 4 ms, faster than 96.25%
    • Memory Usage: 4.3 MB, less than 100.00%

• 392. Is Subsequence

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00% (4 ms, faster than 100.00%)
    • Memory Usage: 2 MB, less than 95.24% (6.4 MB, less than 100.00%)

• 402. Remove K Digits

  • Medium
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 3.4 MB, less than 50.00%
  • Retry to find a better solution

• 438. Find All Anagrams in a String

  • Medium
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 5.1 MB, less than 100.00%

• 443. String Compression

  • Medium
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 5 MB, less than 100.00%

• 451. Sort Characters By Frequency

  • Medium
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 5 MB, less than 100.00%

• 468. Validate IP Address

  • Medium
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2 MB, less than 15.38%

• 476. Number Complement

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 1.9 MB, less than 100.00%

• 509. Fibonacci Number

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 1.9 MB, less than 100.00%

• 525. Contiguous Array

  • Medium
  • Roughly Solved: O(N^2)
    • Runtime: 672 ms, faster than 5.10%
    • Memory Usage: 7 MB, less than 100.00%
  • retry

• 528. Random Pick with Weight

  • Medium
  • Completely Solved (Performance is depending on random inputs)
    • Runtime: 44 ms, faster than 97.83%
    • Memory Usage: 7.8 MB, less than 43.48%

• 540. Single Element in a Sorted Array

  • Medium
  • Completely Solved
    • Runtime: 4 ms, faster than 100.00%
    • Memory Usage: 4.1 MB, less than 100.00%

• 567. Permutation in String

  • Medium
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2.7 MB, less than 100.00%

• 581. Shortest Unsorted Continuous Subarray

  • Easy
  • Completely Solved
    • Runtime: 24 ms, faster than 96.91%
    • Memory Usage: 6.2 MB, less than 100.00%

• 658. Find K Closest Elements

  • Medium
  • Completely Solved
    • Runtime: 180 ms, faster than 100.00%
    • Memory Usage: 8.4 MB, less than 100.00%
  • retry using binary search

• 687. Longest Univalue Path

  • Easy
  • Completely Solved (Original)
    • Runtime: 68 ms, faster than 100.00%
    • Memory Usage: 6.9 MB, less than 100.00%

• 695. Max Area of Island

  • Medium
  • Completely Solved
    • Runtime: 4 ms, faster than 100.00%
    • Memory Usage: 5 MB, less than 100.00%

• 700. Search in a Binary Search Tree

  • Easy
  • Completely Solved
    • Runtime: 24 ms, faster than 94.68%
    • Memory Usage: 6.6 MB, less than 100.00%

• 704. Binary Search

  • Easy
  • Completely Solved
    • Runtime: 32 ms, faster than 96.84%
    • Memory Usage: 6.5 MB, less than 50.00% (This must be the best score)

• 705. Design HashSet

  • Easy
  • Completely Solved
    • Runtime: 80 ms, faster than 97.26%
    • Memory Usage: 8.4 MB, less than 100.00%

• 746. Min Cost Climbing Stairs

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2.9 MB, less than 100.00%

• 771. Jewels and Stones

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2 MB, less than 100.00%

• 787. Cheapest Flights Within K Stops

  • Medium
  • Completely Solved
    • Runtime: 4 ms, faster than 100.00%
    • Memory Usage: 4.4 MB, less than 71.43%

• 791. Custom Sort String

  • Medium
  • Completely Solved (Go)
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2 MB, less than 100.00%
  • Completely Solved (Python3)
    • Runtime: 24 ms, faster than 98.70%
    • Memory Usage: 12.7 MB, less than 100.00%

• 792. Number of Matching Subsequences

  • Medium
  • Completely Solved
    • Runtime: 32 ms, faster than 100.00%
    • Memory Usage: 6.5 MB, less than 96.30%

• 804. Unique Morse Code Words

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2.2 MB, less than 100.00%

• 832. Flipping an Image

  • Easy
  • Completely Solved
    • Runtime: 4 ms, faster than 94.34%
    • Memory Usage: 3.7 MB, less than 100.00%

• 845. Longest Mountain in Array

  • Medium
  • Completely Solved
    • Runtime: 12 ms, faster than 100.00%
    • Memory Usage: 5.9 MB, less than 100.00%
  • find out an another solution

• 859. Buddy Strings

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2.5 MB, less than 100.00%

• 876. Middle of the Linked List

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2 MB, less than 100.00%

• 901. Online Stock Span

  • Medium
  • Completely Solved
    • Runtime: 212 ms, faster than 28.57%
    • Memory Usage: 8.2 MB, less than 100.00%

• 929. Unique Email Addresses

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 5.9 MB, less than 80.00%

• 933. Number of Recent Calls

  • Easy
  • Completely Solved
    • Runtime: 120 ms, faster than 100.00%
    • Memory Usage: 9.8 MB, less than 100.00% (Min score: 8.1 MB)

• 941. Valid Mountain Array

  • Easy
  • Completely Solved
    • Runtime: 24 ms, faster than 89.92%
    • Memory Usage: 6.3 MB, less than 100.00%

• 977. Squares of a Sorted Array

  • Easy
  • Completely Solved
    • Runtime: 24 ms, faster than 100.00%
    • Memory Usage: 6.5 MB, less than 100.00%

• 986. Interval List Intersections

  • Medium
  • Completely Solved
    • Runtime: 16 ms, faster than 97.97%
    • Memory Usage: 6.3 MB, less than 100.00%

• 999. Available Captures for Rook

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 1.9 MB, less than 100.00%

• 1005. Maximize Sum Of Array After K Negations

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2.9 MB, less than 100.00%

• 1008. Construct Binary Search Tree from Preorder Traversal

  • Medium
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 3.2 MB, less than 100.00%

• 1009. Complement of Base 10 Integer

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 1.9 MB, less than 100.00%

• 1035. Uncrossed Lines

  • Medium
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2.3 MB, less than 100.00%

• 1037. Valid Boomerang

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2 MB, less than 100.00%

• 1051. Height Checker

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2.2 MB, less than 100.00%

• 1071. Greatest Common Divisor of Strings

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2.3 MB, less than 100.00%

• 1105. Filling Bookcase Shelves

  • Medium
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 4.3 MB, less than 100.00%
  • retry

• 1184. Distance Between Bus Stops

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2.8 MB, less than 100.00%

• 1217. Play with Chips

  • Easy
  • Weekly Contest 157 01
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2.1 MB, less than 100.00%

• 1219. Path with Maximum Gold

  • Medium
  • Weekly Contest 157 03
  • Roughly Solved
    • Runtime: 140 ms, faster than 11.94%
    • Memory Usage: 2.6 MB, less than 100.00%

• 1221. Split a String in Balanced Strings

  • Easy
  • Weekly Contest 158 01
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2 MB, less than 100.00%

• 1222. Queens That Can Attack the King

  • Medium
  • Weekly Contest 158 02
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2.5 MB, less than 100.00%

• 1232. Check If It Is a Straight Line

  • Easy
  • Weekly Contest 159 01
  • Completely Solved
    • Runtime: 4 ms, faster than 94.37%
    • Memory Usage: 3.7 MB, less than 100.00%

• 1233. Remove Sub-Folders from the Filesystem

  • Medium
  • Weekly Contest 159 02
  • Completely Solved
    • Runtime: X ms, faster than 100.00%
    • Memory Usage: X MB, less than 100.00%

• 1234. Replace the Substring for Balanced String

  • Medium
  • Weekly Contest 159 03
  • Completely Solved
    • Runtime: X ms, faster than 100.00%
    • Memory Usage: X MB, less than 100.00%

• 1252. Cells with Odd Values in a Matrix

  • Easy
  • Weekly Contest 162 01
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2.5 MB, less than 100.00%

• 1275. Find Winner on a Tic Tac Toe Game

  • Easy
  • Weekly Contest 165 01
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2 MB, less than 100.00%

• 1365. How Many Numbers Are Smaller Than the Current Number

  • Easy
  • Weekly Contest 178 01
  • Completely Solved
    • Runtime: 4 ms, faster than 100.00%
    • Memory Usage: 3.1 MB, less than 100.00%

• 1374. Generate a String With Characters That Have Odd Counts

  • Easy
  • Weekly Contest 179 01
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2.1 MB, less than 100.00%

• 1375. Bulb Switcher III

  • Medium
  • Weekly Contest 179 02
  • Completely Solved
    • Runtime: 56 ms, faster than 100.00%
    • Memory Usage: 7.1 MB, less than 100.00%

• 1376. Time Needed to Inform All Employees

  • Medium
  • Weekly Contest 179 03
  • Completely Solved
    • Runtime: 156 ms, faster than 100.00%
    • Memory Usage: 10.6 MB, less than 100.00%

• 1380. Lucky Numbers in a Matrix

  • Easy
  • Weekly Contest 180 01
  • Completely Solved
    • Runtime: 16 ms, faster than 100.00%
    • Memory Usage: 6 MB, less than 100.00%

• 1389. Create Target Array in the Given Order

  • Easy
  • Weekly Contest 181 01
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2.1 MB, less than 100.00%

• 1408. String Matching in an Array

  • Easy
  • Completely Solved
    • Runtime: 0 ms, faster than 100.00%
    • Memory Usage: 2.3 MB, less than 100.00%

Posts

• Binary Search and Cumulative Sum solution in Go
• Only 3 lines of code in Go 😎, Time: 4 ms - O(logN), Space: 4.1 MB - O(1)
• The coolest solution using bit manipulation in Go
• The clearest solution in Go, Runtime: 0 ms Memory Usage: 2.1 MB
• The lucky number appears in a Matrix at most once, Time: O(N*M) Space: O(N)
• Two ways of DFS solutions (from bottom to top, from top to bottom) in Go
• Time: O(l+n+m) Space: O(n+m), the clearest solution in Go
• O(N), O(NlogN), O(n^2) 3 + α different solutions in Go
• Dynamically modified multi-layer arrays solution in Go
• Clear solution using a 3x3 int array and char code in Go
• Just 1 line solution 💪🔥 (with another expected regular solution😂) in Go
• 4 + 1 (20 ms, 6.3MB) different solutions in Go
• 4 different solutions in Go
• Clear divide and conquer approach in Go

Helpers

• BuildTreeNode
  • Build TreeNode from LeetCode's TreeNode string