The Elite Problem Bank

Crush the
"Impossible" Problems.

50+ hand-picked FAANG problems with deep intuition, O(1) space optimizations, and interview scripts.

1Hard Graph Patterns

Hard3 MIN Walkthrough

Problem 8: Alien Dictionary (Hard)

Staff+ Architect

Hard3 MIN Walkthrough

Problem 17: Word Ladder (Hard)

Staff+ Architect

Hard3 MIN Walkthrough

Problem 28: Word Ladder II (Hard)

Staff+ Architect

Hard4 MIN Walkthrough

Problem 40: Swim in Rising Water (Hard)

Staff+ Architect

Hard4 MIN Walkthrough

Problem 41: Making A Large Island (Hard)

Staff+ Architect

Hard4 MIN Walkthrough

Problem 43: Cut Off Trees for Golf Event (Hard)

Staff+ Architect

Hard3 MIN Walkthrough

Problem 44: Race Car (Hard)

Staff+ Architect

Hard4 MIN Walkthrough

Problem 47: Valid Arrangement of Pairs (Hard)

Staff+ Architect

Hard3 MIN Walkthrough

Problem 48: Parallel Courses III (Hard)

Staff+ Architect

Hard4 MIN Walkthrough

Problem 50: Sliding Puzzle (Hard)

Staff+ Architect

2Hard DP Patterns

Hard3 MIN Walkthrough

Problem 29: Burst Balloons (Hard)

Staff+ Architect

Hard2 MIN Walkthrough

Problem 32: Word Break II (Hard)

Staff+ Architect

Hard3 MIN Walkthrough

Problem 35: Maximum Profit in Job Scheduling (Hard)

Staff+ Architect

Hard4 MIN Walkthrough

Problem 45: Maximize Score After N Operations (Hard)

Staff+ Architect

Hard3 MIN Walkthrough

Problem 46: Count Vowels Permutation (Hard)

Staff+ Architect

3Hard String Patterns

Hard3 MIN Walkthrough

Problem 11: Longest Valid Parentheses (Hard)

Staff+ Architect

Hard3 MIN Walkthrough

Problem 13: Edit Distance (Hard)

Staff+ Architect

Hard3 MIN Walkthrough

Problem 15: Basic Calculator II (Hard)

Staff+ Architect

Hard3 MIN Walkthrough

Problem 23: Minimum Window Subsequence (Hard)

Staff+ Architect

Hard3 MIN Walkthrough

Problem 31: Regular Expression Matching (Hard)

Staff+ Architect

Hard3 MIN Walkthrough

Problem 38: Palindrome Pairs (Hard)

Staff+ Architect

4Hard Design Patterns

Hard3 MIN Walkthrough

Problem 5: LRU Cache Design (Hard)

Staff+ Architect

Hard3 MIN Walkthrough

Problem 16: LFU Cache Design (Hard)

Staff+ Architect

Hard3 MIN Walkthrough

Problem 34: Find Median from Data Stream (Hard)

Staff+ Architect

Hard4 MIN Walkthrough

Problem 39: Design Search Autocomplete System (Hard)

Staff+ Architect

Hard3 MIN Walkthrough

Problem 42: Design In-Memory File System (Hard)

Staff+ Architect

Hard3 MIN Walkthrough

Problem 49: Prefix and Suffix Search (Hard)

Staff+ Architect

5Hard Binary Search

Hard3 MIN Walkthrough

Problem 2: Median of Two Sorted Arrays (Hard)

Staff+ Architect

6Hard List Patterns

Hard3 MIN Walkthrough

Problem 4: Merge K Sorted Lists (Hard)

Staff+ Architect

Hard3 MIN Walkthrough

Problem 7: Reverse Nodes in k-Group (Hard)

Staff+ Architect

7Hard Backtracking Patterns

Hard3 MIN Walkthrough

Problem 10: Sudoku Solver (Hard)

Staff+ Architect

Hard3 MIN Walkthrough

Problem 12: N-Queens (Hard)

Staff+ Architect

8Hard Array Patterns

Hard3 MIN Walkthrough

Problem 1: Trapping Rain Water (Hard)

Staff+ Architect

Hard3 MIN Walkthrough

Problem 6: Sliding Window Maximum (Hard)

Staff+ Architect

Hard3 MIN Walkthrough

Problem 24: Employee Free Time (Hard)

Staff+ Architect

Hard3 MIN Walkthrough

Problem 26: Largest Rectangle in Histogram (Hard)

Staff+ Architect

Hard3 MIN Walkthrough

Problem 27: First Missing Positive (Hard)

Staff+ Architect

Hard3 MIN Walkthrough

Problem 30: Smallest Range Covering Elements from K Lists (Hard)

Staff+ Architect

Hard3 MIN Walkthrough

Problem 33: Insert Interval (Hard)

Staff+ Architect

Hard3 MIN Walkthrough

Problem 37: Minimum Number of K Consecutive Bit Flips (Hard)

Staff+ Architect

9Hard Tree Patterns

Hard3 MIN Walkthrough

Problem 9: Binary Tree Maximum Path Sum (Hard)

Staff+ Architect

Hard3 MIN Walkthrough

Problem 14: K-th Smallest in Lexicographical Order (Hard)

Staff+ Architect

Hard3 MIN Walkthrough

Problem 21: Serialize and Deserialize Binary Tree (Hard)

Staff+ Architect

Hard3 MIN Walkthrough

Problem 36: Serialize and Deserialize BST (Hard)

Staff+ Architect

10Hard Matrix Patterns

Hard3 MIN Walkthrough

Problem 3: Word Search II (Hard)

Staff+ Architect

Hard3 MIN Walkthrough

Problem 22: Longest Increasing Path in a Matrix (Hard)

Staff+ Architect

Hard3 MIN Walkthrough

Problem 25: Maximal Rectangle (Hard)

Staff+ Architect

"The difference between a Senior and a Staff Engineer is the ability to see patterns where others see chaos."

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