Problem-solving / The list
The 100 problems
One hundred interview problems worth knowing cold. The base is the canonical lists — Blind 75, NeetCode 150, Grind 75 — rounded out and re-weighted with current company tags. Every one of the twenty-five patterns is represented. Filter by pattern, difficulty, or company; each problem has its own page with an interactive walkthrough.
20 easy · 65 medium · 15 hard · 39 with live simulators
Difficulty
100 of 100 problems
Arrays & Hashing 9
Two Pointers 5
Sliding Window 6
Stack 6
Binary Search 6
Linked List 7
Trees 10
- LC 226 Invert Binary Tree Easy
- LC 104 Maximum Depth of Binary Tree Easy
- LC 543 Diameter of Binary Tree Easy
- LC 110 Balanced Binary Tree Easy
- LC 102 Binary Tree Level Order Traversal Medium
- LC 98 Validate Binary Search Tree Medium
- LC 230 Kth Smallest Element in a BST Medium
- LC 235 Lowest Common Ancestor of a BST Medium
- LC 124 Binary Tree Maximum Path Sum Hard
- LC 297 Serialize and Deserialize Binary Tree Hard