A* Pathfinding Heuristic
Implement A* search on a 2D grid to find the shortest path length between two cells.
Swim in Rising Water
Find the minimum time needed to swim from the top-left to the bottom-right of a grid where water level rises and you can only move to cells with elevation ≤ current time.
Surrounded Regions
Given an M×N grid of 'X' and 'O', capture all regions of 'O' that are completely surrounded by 'X'.
Android unlock patterns
Count the number of valid Android unlock patterns of a given length using a 3x3 grid with adjacency constraints.
Most stones removed
Given stone coordinates on a grid, find the maximum number of stones that can be removed while every stone shares a row or column with another remaining stone.
Showing 1–5 of 5 challenges · Graphs & Graph Algorithms
Graphs & Graph Algorithms — Python coding challenges
What you will find here
This page lists graphs & graph algorithms 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.