Python coding challenges: "del"

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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

Python Basics easy

Garbage Collection Hint

Write a function that predicts when an object is garbage collected based on reference counting.

garbage-collection reference-counting object-lifecycle

+10 pts 10m

Iterators & Generators easy

Yield from delegation

Implement a generator that flattens nested iterables of any depth using `yield from`.

generators yield delegation

+8 pts 10m

Trees & Binary Trees medium

Delete Node in BST

Implement a function that deletes a key from a binary search tree and returns the new root.

binary-search-tree tree-traversal recursion

+20 pts 20m

Graphs & Graph Algorithms medium

Network Delay Time

Given a directed weighted graph and a starting node, find the minimum time for a signal to reach all nodes, or -1 if unreachable.

dijkstra shortest-path graph

+25 pts 30m

Showing 4 challenges

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