Evaluate Reverse Polish Notation
Evaluate an arithmetic expression written in reverse Polish notation using a stack.
Daily Temperatures
Given a list of daily temperatures, return for each day how many days until a warmer temperature appears.
Decode String Stack
Decode a compressed string with repeated substrings like '3[a2[c]]' to 'accaccacc' using a stack-based approach.
Remove K Digits Stack
Remove k digits from a non-negative integer string to produce the smallest possible number using a stack-based approach.
Score of Parentheses
Given a balanced parentheses string, compute its score where () is 1 and concatenation sums, nesting multiplies by 2.
Validate Stack Sequences
Given two sequences of distinct integers, verify whether the second sequence is a valid pop order for a stack given the first sequence as push order.
Buildings with ocean view
Given building heights, return sorted indices of buildings that have a clear view of the ocean to their right.
Sum of Subarray Minimums
Given an integer array, sum the minimum of all contiguous subarrays modulo 10^9+7.
Asteroid Collision
Simulate asteroid collisions with a stack and return the remaining asteroids in original order.
Decode Nested String
Implement a function that decodes a string with nested encoding patterns.
Showing 1–10 of 10 challenges · medium · Stacks & Queues
Stacks & Queues — Python coding challenges
What you will find here
This page lists stacks & queues challenges — real Python problems you solve in the browser IDE with instant test feedback. Each challenge includes a clear brief, starter code, and automated checks.
Challenges vs tutorials and quizzes
Challenges test what you can build under constraints. For guided teaching, use our Python tutorials. For quick checks, try quizzes or copy snippets from code samples.