~/problems
Problems
Basics first, then the classics, then company-style assessments. Every problem has tests you run right here; multi-level ones unlock as you go. See the roadmap.
Interview roadmap
Stacks
Matching brackets, paths, next greater element.
24 problems
Interview roadmap
Stacks Matching brackets, paths, next greater element.
Stacks guide
- Basics: an undo log with a stack basics py · c++ · java easy
- Valid Parentheses py · c++ · java easy
- Implement Queue Using Stacks py · c++ · java easy
- Min Stack py · c++ · java medium
- Evaluate Reverse Polish Notation py · c++ · java medium
- Asteroid Collision py · c++ · java medium
- Decode String py · c++ · java medium
- Maximum Frequency Stack py · c++ · java hard
Monotonic stack guide
- Basics: nearest smaller value to the left basics py · c++ · java easy
- Messages between signal towers py · c++ · java easy
- Daily Temperatures py · c++ · java easy
- Next Greater Element I py · c++ · java easy
- Largest Rectangle in Histogram py · c++ · java hard
- Trapping Rain Water py · c++ · java medium
- Car Fleet py · c++ · java medium
- Online Stock Span py · c++ · java medium
Stack: path parsing guide
- Basics: balanced brackets with a stack basics py · c++ · java easy
- Where each piece of text lives py · c++ · java easy
- Simplify Path py · c++ · java easy
- OA: cd with ~ and symlinks 3 levels OpenAI hard
- OA: Stack trace reconstruction 3 levels Anthropic medium
- OA: Fewest deletions to balance parentheses 2 levels DoorDash easy
- CPU usage analysis Uber medium
- Longest valid ranked-bracket substring Uber py · c++ · java hard