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LeetCode Solutions

LeetCode 75

Summary

75 Essential & Trending Problems Must-do problem list for interview prep Best for 1~3 month of prep time

I. Array / String

• 01. Merge Strings Alternately
• 02. Greatest Common Divisor of Strings
• 03. Kids With the Greatest Number of Candies
• 04. Can Place Flowers
• 05. Reverse Vowels of a String
• 06. Reverse Words in a String
• 07. Product of Array Except Self
• 08. Increasing Triplet Subsequence
• 09. String Compression

II. Two Pointers

• 10. Move Zeroes
• 11. Is Subsequence
• 12. Container With Most Water
• 13. Max Number of K-Sum Pairs

III. Sliding Window

• 14. Maximum Average Subarray I
• 15. Maximum Number of Vowels in a Substring of Given Length
• 16. Max Consecutive Ones III
• 17. Longest Subarray of 1's After Deleting One Element

IV. Prefix Sum

• 18. Find the Highest Altitude
• 19. Find Pivot Index

V. Hash Map / Set

• 20. Find the Difference of Two Arrays
• 21. Unique Number of Occurrences
• 22. Determine if Two Strings Are Close
• 23. Equal Row and Column Pairs

VI. Stack

• 24. Removing Stars From a String
• 25. Asteroid Collision
• 26. Decode String

VII. Queue

• 27. Number of Recent Calls
• 28. Dota2 Senate

VIII. Linked List

• 29. Delete the Middle Node of a Linked List
• 30. Odd Even Linked List
• 31. Reverse Linked List
• 32. Maximum Twin Sum of a Linked List

IX. Binary Tree - DFS

• 33. Maximum Depth of Binary Tree
• 34. Leaf-Similar Trees
• 35. Count Good Nodes in Binary Tree
• 36. Path Sum III
• 37. Longest ZigZag Path in a Binary Tree
• 38. Lowest Common Ancestor of a Binary Tree

X. Binary Tree - BFS

• 39. Binary Tree Right Side View
• 40. Maximum Level Sum of a Binary Tree

XI. Binary Search Tree

• 41. Search in a Binary Search Tree
• 42. Delete Node in a BST

XII. Graphs - DFS

• 43. Keys and Rooms
• 44. Number of Provinces
• 45. Reorder Routes to Make All Paths Lead to the City Zero
• 46. Evaluate Division

XIII. Graphs - BFS

• 47. Nearest Exit from Entrance in Maze
• 48. Rotting Oranges

XIV. Heap / Priority Queue

• 49. Kth Largest Element in an Array
• 50. Smallest Number in Infinite Set
• 51. Maximum Subsequence Score
• 52. Total Cost to Hire K Workers

XV. Binary Search

• 53. Guess Number Higher or Lower
• 54. Successful Pairs of Spells and Potions
• 55. Find Peak Element
• 56. Koko Eating Bananas

XVI. Backtracking

• 57. Letter Combinations of a Phone Number
• 58. Combination Sum III

XVII. DP - 1D

• 59. N-th Tribonacci Number
• 60. Min Cost Climbing Stairs
• 61. House Robber
• 62. Domino and Tromino Tiling

XVIII. DP - Multidimensional

• 63. Unique Paths
• 64. Longest Common Subsequence
• 65. Best Time to Buy and Sell Stock with Transaction Fee
• 66. Edit Distance

XIX. Bit Manipulation

• 67. Counting Bits
• 68. Single Number
• 69. Minimum Flips to Make a OR b Equal to c

XX. Trie

• 70. Implement Trie (Prefix Tree)
• 71. Search Suggestions System

XXI. Intervals

• 72. Non-overlapping Intervals
• 73. Minimum Number of Arrows to Burst Balloons

XXII. Monotonic Stack

• 74. Daily Temperatures
• 75. Online Stock Span

LeetCode 150

Summary

150 Original & Classic Questions Covers comprehensive interview topics Best for 3+ months of prep time