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Python Coding Challenges

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819 challenges 506 easy 280 medium 33 hard
Graphs & Graph Algorithms medium

Bellman-Ford Algorithm

Implement the Bellman-Ford algorithm to compute shortest distances from a source in a directed weighted graph with up to 100 vertices and negative edges.

shortest-path negative-edges graph
+30 pts 30m
Graphs & Graph Algorithms medium

Graph Coloring

Given an undirected graph, determine if it can be colored with two colors such that adjacent vertices have different colors.

graph bipartite bfs
+20 pts 20m
Graphs & Graph Algorithms medium

Course Schedule Can Finish

Given numCourses and prerequisites, return whether all courses can be finished without cyclic dependencies.

graph cycle topological
+25 pts 30m
Graphs & Graph Algorithms medium

Cheapest Flights Within K Stops

Implement a function to compute the cheapest flight price from source to destination with at most K stops in a directed weighted graph.

graphs shortest-path dp
+30 pts 30m
Graphs & Graph Algorithms medium

Possible bipartition

Given N people and a list of mutual dislikes, check if they can be divided into two groups with no dislike inside a group.

bipartite graph bfs
+25 pts 25m
Graphs & Graph Algorithms medium

Android unlock patterns

Count the number of valid Android unlock patterns of a given length using a 3x3 grid with adjacency constraints.

graphs dfs backtracking
+25 pts 30m
Graphs & Graph Algorithms medium

Floyd-Warshall: All-Pairs Shortest Paths

Implement the Floyd-Warshall algorithm to find all-pairs shortest path distances in a directed graph with possibly negative weights but no negative cycles.

graph shortest-path dynamic-programming
+25 pts 30m

Showing 7 challenges · medium · 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.