Python coding challenges: "reachability"

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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

Matrix & 2D Arrays medium

Pacific Atlantic Matrix DFS

Given a matrix of heights, return cells that can reach both Pacific and Atlantic oceans using a DFS approach.

dfs matrix traversal

+20 pts 20m

Showing 2 challenges · medium

Guide: free Python coding challenges

Practice Python by solving problems

PythonSkillset challenges are hands-on coding exercises from beginner to advanced. Open a challenge, read the problem, write Python in the split-pane editor, and run tests with Pyodide — no install required.

How to use the arena

Pick a category — basics, algorithms, strings, and more
Open a challenge, read the statement, and edit the starter code
Run tests, fix failures, then try a related quiz or tutorial lesson

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.

Python Coding Challenges