Cloze

‹ Quests

The Blind 75

The classic interview list, one stage at a time.

Seventy-five problems in ten chapters, from arrays to heaps. Each stage has three trials: recall the key lines, rebuild a loop or a block, then write the whole function with a safety net.

Sign in to keep your stars

Chapter 1

Arrays

Hash maps, prefix products and the first habits of a careful solver.

10 of 10 stages written

  1. 1 Two Sum Hash map Ready
  2. 2 Best Time to Buy and Sell Stock One pass Ready
  3. 3 Contains Duplicate Hash set Ready
  4. 4 Product of Array Except Self Prefix and suffix products Ready
  5. 5 Maximum Subarray Running best Ready
  6. 6 Maximum Product Subarray Running best and worst Ready
  7. 7 Find Minimum in Rotated Sorted Array Binary search Ready
  8. 8 Search in Rotated Sorted Array Binary search Ready
  9. 9 3Sum Sort and two pointers Ready
  10. 10 Container With Most Water Two pointers Ready

Chapter 2

Binary

Bits: counting, flipping and adding without a plus.

0 of 5 stages written

  1. 11 Sum of Two Integers Not written yet Coming
  2. 12 Number of 1 Bits Not written yet Coming
  3. 13 Counting Bits Not written yet Coming
  4. 14 Missing Number Not written yet Coming
  5. 15 Reverse Bits Not written yet Coming

Chapter 3

Dynamic programming

Break a problem into smaller ones you have already solved.

0 of 11 stages written

  1. 16 Climbing Stairs Not written yet Coming
  2. 17 Coin Change Not written yet Coming
  3. 18 Longest Increasing Subsequence Not written yet Coming
  4. 19 Longest Common Subsequence Not written yet Coming
  5. 20 Word Break Not written yet Coming
  6. 21 Combination Sum IV Not written yet Coming
  7. 22 House Robber Not written yet Coming
  8. 23 House Robber II Not written yet Coming
  9. 24 Decode Ways Not written yet Coming
  10. 25 Unique Paths Not written yet Coming
  11. 26 Jump Game Not written yet Coming

Chapter 4

Graphs

Search a world of connected things: islands, courses, clones.

0 of 8 stages written

  1. 27 Clone Graph Not written yet Coming
  2. 28 Course Schedule Not written yet Coming
  3. 29 Pacific Atlantic Water Flow Not written yet Coming
  4. 30 Number of Islands Not written yet Coming
  5. 31 Longest Consecutive Sequence Not written yet Coming
  6. 32 Alien Dictionary Not written yet Coming
  7. 33 Graph Valid Tree Not written yet Coming
  8. 34 Number of Connected Components in an Undirected Graph Not written yet Coming

Chapter 5

Intervals

Ranges on a line: merge them, insert into them, schedule around them.

0 of 5 stages written

  1. 35 Insert Interval Not written yet Coming
  2. 36 Merge Intervals Not written yet Coming
  3. 37 Non-overlapping Intervals Not written yet Coming
  4. 38 Meeting Rooms Not written yet Coming
  5. 39 Meeting Rooms II Not written yet Coming

Chapter 6

Linked lists

Pointers you rewire by hand.

1 of 6 stages written

  1. 40 Reverse Linked List Linked list Ready
  2. 41 Linked List Cycle Not written yet Coming
  3. 42 Merge Two Sorted Lists Not written yet Coming
  4. 43 Merge K Sorted Lists Not written yet Coming
  5. 44 Remove Nth Node From End of List Not written yet Coming
  6. 45 Reorder List Not written yet Coming

Chapter 7

Matrices

Grids: walk them, rotate them, search them.

0 of 4 stages written

  1. 46 Set Matrix Zeroes Not written yet Coming
  2. 47 Spiral Matrix Not written yet Coming
  3. 48 Rotate Image Not written yet Coming
  4. 49 Word Search Not written yet Coming

Chapter 8

Strings

Windows, anagrams, brackets and palindromes.

1 of 10 stages written

  1. 50 Longest Substring Without Repeating Characters Not written yet Coming
  2. 51 Longest Repeating Character Replacement Not written yet Coming
  3. 52 Minimum Window Substring Not written yet Coming
  4. 53 Valid Anagram Not written yet Coming
  5. 54 Group Anagrams Not written yet Coming
  6. 55 Valid Parentheses Stack Ready
  7. 56 Valid Palindrome Not written yet Coming
  8. 57 Longest Palindromic Substring Not written yet Coming
  9. 58 Palindromic Substrings Not written yet Coming
  10. 59 Encode and Decode Strings Not written yet Coming

Chapter 9

Trees

Recursion on branching shapes, and search trees.

0 of 14 stages written

  1. 60 Maximum Depth of Binary Tree Not written yet Coming
  2. 61 Same Tree Not written yet Coming
  3. 62 Invert Binary Tree Not written yet Coming
  4. 63 Binary Tree Maximum Path Sum Not written yet Coming
  5. 64 Binary Tree Level Order Traversal Not written yet Coming
  6. 65 Serialize and Deserialize Binary Tree Not written yet Coming
  7. 66 Subtree of Another Tree Not written yet Coming
  8. 67 Construct Binary Tree from Preorder and Inorder Traversal Not written yet Coming
  9. 68 Validate Binary Search Tree Not written yet Coming
  10. 69 Kth Smallest Element in a BST Not written yet Coming
  11. 70 Lowest Common Ancestor of a Binary Search Tree Not written yet Coming
  12. 71 Implement Trie (Prefix Tree) Not written yet Coming
  13. 72 Design Add and Search Words Data Structure Not written yet Coming
  14. 73 Word Search II Not written yet Coming

Chapter 10

Heaps

Always know the smallest, largest or middle.

0 of 3 stages written

  1. 74 Merge K Sorted Lists Not written yet Coming
  2. 75 Top K Frequent Elements Not written yet Coming
  3. 76 Find Median from Data Stream Not written yet Coming