Python Coding Challenges · PythonSkillset

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All Python Basics Strings & Text Lists & Arrays Dicts & Sets Functions & Closures OOP & Classes Data Structures & Algorithms Advanced Python Iterators & Generators Decorators & Context Managers Error Handling & Exceptions Regular Expressions Math & Number Theory Bit Manipulation Dynamic Programming Trees & Binary Trees Graphs & Graph Algorithms Recursion & Backtracking Greedy Algorithms Binary Search Two Pointers & Sliding Window Stacks & Queues Heaps & Priority Queues Linked Lists Matrix & 2D Arrays Datetime & Time Calculations Data Formats & Parsing SQL & SQLite Numpy & Vectorized Computing Cryptography & Hashing

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

Graphs & Graph Algorithms medium

Jump Game on Graph

Implement a function that determines if you can reach the last node of a directed graph by jumping from node 0 to node n-1 using edges.

graphs bfs reachability

+25 pts 30m

Graphs & Graph Algorithms medium

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.

graphs dfs union-find

+30 pts 30m

Showing 25–28 of 28 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.