Blind 75

The Blind 75 is a curated list of 75 essential LeetCode coding problems designed to prepare software engineers for technical interviews at top tech companies.

Video walkthroughs

• Contains Duplicate - LeetCode 217 - Hash Set (Python & Java) (7:49)
• Valid Anagram - LeetCode 242 - Hash Map (Python & Java) (6:25)
• Two Sum - LeetCode 1 - Hash Map (Python & Java) (8:38)
• Group Anagrams - LeetCode 49 - Hash Map (Python & Java) (11:34)
• Top K Frequent Elements - LeetCode 347 - Buckets (Python & Java) (12:06)
• Encode and Decode Strings - LeetCode 271 (Python & Java) (11:04)
• Product of Array Except Self - LeetCode 238 (Python & Java) (10:18)
• Longest Consecutive Sequence - LeetCode 128 (Python & Java) (9:51)
• Valid Palindrome - LeetCode 125 - Two Pointers (Python & Java) (8:10)
• 3Sum - LeetCode 15 - Two Pointers (Python & Java) (10:52)
• Container With Most Water - LeetCode 11 - Two Pointers (Python & Java) (5:39)
• Best Time to Buy and Sell Stock - LeetCode 121 - Sliding Window (Python & Java) (5:12)
• Longest Substring Without Repeating Characters - LeetCode 3 - Sliding Window (Python & Java) (5:37)
• Longest Repeating Character Replacement - LeetCode 424 - Sliding Window (Python & Java) (5:55)
• Minimum Window Substring - LeetCode 76 - Sliding Window (Python & Java) (6:24)
• Valid Parentheses - LeetCode 20: One Stack, Three Ways to Return False (Python & Java) (5:38)
• Find Minimum in Rotated Sorted Array - LeetCode 153: Binary Search for the Drop (Python & Java) (5:16)
• Search in Rotated Sorted Array - LeetCode 33: Which Half Is Sorted? (Python & Java) (5:51)
• Reverse Linked List - LeetCode 206: Three Pointers, One Pass (Python & Java) (4:41)
• Merge Two Sorted Lists - LeetCode 21: Dummy Node and a Tail Pointer (Python & Java) (5:28)
• Linked List Cycle - LeetCode 141: Why Fast Always Catches Slow (Floyd's, Python & Java) (5:08)
• Reorder List - LeetCode 143: Split, Reverse, Weave in O(1) Space (Python & Java) (5:39)
• Remove Nth Node From End of List - LeetCode 19: One Pass with a Dummy Node (Python & Java) (5:01)

All 75 problems

1. Contains Duplicate Easy
2. Valid Anagram Easy
3. Two Sum Easy
4. Group Anagrams Medium
5. Top K Frequent Elements Medium
6. Encode and Decode Strings Medium
7. Product of Array Except Self Medium
8. Longest Consecutive Sequence Medium
9. Valid Palindrome Easy
10. 3Sum Medium
11. Container With Most Water Medium
12. Best Time to Buy and Sell Stock Easy
13. Longest Substring Without Repeating Characters Medium
14. Longest Repeating Character Replacement Medium
15. Minimum Window Substring Hard
16. Valid Parentheses Easy
17. Find Minimum in Rotated Sorted Array Medium
18. Search in Rotated Sorted Array Medium
19. Reverse Linked List Easy
20. Merge Two Sorted Lists Easy
21. Linked List Cycle Easy
22. Reorder List Medium
23. Remove Nth Node From End of List Medium
24. Merge K Sorted Lists Hard
25. Invert Binary Tree Easy
26. Maximum Depth of Binary Tree Easy
27. Same Tree Easy
28. Subtree of Another Tree Easy
29. Lowest Common Ancestor of a Binary Search Tree Medium
30. Binary Tree Level Order Traversal Medium
31. Validate Binary Search Tree Medium
32. Kth Smallest Element in a BST Medium
33. Construct Binary Tree from Preorder and Inorder Traversal Medium
34. Binary Tree Maximum Path Sum Hard
35. Serialize and Deserialize Binary Tree Hard
36. Find Median from Data Stream Hard
37. Combination Sum Medium
38. Word Search Medium
39. Implement Trie (Prefix Tree) Medium
40. Design Add and Search Words Data Structure Medium
41. Word Search II Hard
42. Number of Islands Medium
43. Clone Graph Medium
44. Pacific Atlantic Water Flow Medium
45. Course Schedule Medium
46. Graph Valid Tree Medium
47. Number of Connected Components in an Undirected Graph Medium
48. Alien Dictionary Hard
49. Climbing Stairs Easy
50. House Robber Medium
51. House Robber II Medium
52. Longest Palindromic Substring Medium
53. Palindromic Substrings Medium
54. Decode Ways Medium
55. Coin Change Medium
56. Maximum Product Subarray Medium
57. Word Break Medium
58. Longest Increasing Subsequence Medium
59. Unique Paths Medium
60. Longest Common Subsequence Medium
61. Maximum Subarray Medium
62. Jump Game Medium
63. Insert Interval Medium
64. Merge Intervals Medium
65. Non Overlapping Intervals Medium
66. Meeting Rooms Easy
67. Meeting Rooms II Medium
68. Rotate Image Medium
69. Spiral Matrix Medium
70. Set Matrix Zeroes Medium
71. Number of 1 Bits Easy
72. Counting Bits Easy
73. Reverse Bits Easy
74. Missing Number Easy
75. Sum of Two Integers Medium

Mock interview