Blind 75 interview practice
Practice like the interviewer is already listening.
Work through each problem by stating the brute force, finding the invariant, dry-running the idea, and only then revealing the Python solution.
75 Blind 75 problems 12-week path Python practice Hints before answers Browser code runner
Today's session
Pick a problem, think first, then code.
Use each page as a guided interview rep. Keep the answer closed until you can explain the invariant out loud.
Follow the weekly path
Start with your current week, then revisit older problems from a blank editor.
Warm up with Two Sum
Practice the complement map, original-index constraint, and one-pass narration.
Run a 20-minute drill
Choose a familiar problem, solve from scratch, and compare your explanation with the reveal.
How to practice
One page, one interview rep.
Move through the reveal sections in order. The goal is not to memorize code; it is to make the reasoning automatic.
- Restate the problem. Name the input, output, constraints, and the brute-force baseline.
- Reveal the ladder slowly. Open each hint only after you have written your own next step.
- Dry-run before code. Track the state by hand on one non-trivial example.
- Code and run tests. Use the browser runner, then compare with the final Python solution.
Choose a pattern
Build fluency one pattern at a time.
Use the week number to stay on schedule, and use difficulty to choose warmups before timed reps.
Arrays & Hashing
Two Pointers
Sliding Window
Stack
Binary Search
Linked List
Trees
- Invert Binary Tree Week 4 · Easy
- Maximum Depth of Binary Tree Week 4 · Easy
- Same Tree Week 4 · Easy
- Subtree of Another Tree Week 4 · Easy
- Lowest Common Ancestor of a Binary Search Tree Week 4 · Medium
- Binary Tree Level Order Traversal Week 4 · Medium
- Validate Binary Search Tree Week 4 · Medium
- Kth Smallest Element in a BST Week 4 · Medium
- Construct Binary Tree from Preorder and Inorder Traversal Week 4 · Medium
- Binary Tree Maximum Path Sum Week 4 · Hard
- Serialize and Deserialize Binary Tree Week 4 · Hard
Graphs
1-D Dynamic Programming
- Climbing Stairs Week 7 · Easy
- House Robber Week 7 · Medium
- House Robber II Week 7 · Medium
- Longest Palindromic Substring Week 7 · Medium
- Palindromic Substrings Week 7 · Medium
- Decode Ways Week 7 · Medium
- Coin Change Week 8 · Medium
- Maximum Product Subarray Week 8 · Medium
- Word Break Week 8 · Medium
- Longest Increasing Subsequence Week 8 · Medium