Split list at index
Return prefix and suffix tuples at index k.
Second node value
Return the second value or None if fewer than two nodes.
Drop the tail node
Return a new list without the last node.
Join node values with arrows
Format string node values as 'a -> b -> c'; empty list returns ''.
Compare two linked lists
Return True when both lists have identical values in order.
Spiral Matrix Order
Given a 2D matrix, return all elements in clockwise spiral order starting from the top-left.
01 Matrix Nearest Zero
Given a binary matrix, return a matrix of the same shape where each cell contains the Manhattan distance to the nearest 0.
Spiral Matrix Traversal
Implement a function that returns the elements of a 2D matrix in clockwise spiral order.
Rotate Image 90 Degrees Clockwise
Rotate a square matrix 90 degrees clockwise and return the rotated matrix.
Diagonal Traverse Matrix
Implement a function that returns all elements of a matrix in diagonal zigzag order.
Transpose Matrix In-Place
Implement a function that transposes a square matrix in-place and returns the transposed matrix.
Matrix Multiply 2D
Write a function that multiplies two 2D matrices (lists of lists) and returns the product matrix.
Transpose 2D Array
Implement a function that returns the transpose of a rectangular 2D list.
Pacific Atlantic Flow
Given a height matrix, return all cells from which water can flow to both the Pacific and Atlantic oceans.
Pacific Atlantic Matrix DFS
Given a matrix of heights, return cells that can reach both Pacific and Atlantic oceans using a DFS approach.
Days in month
Write a function that returns the number of days in a given month and year, correctly handling leap years.
Days Between Dates
Write a function that returns the number of days between two given dates.
Add Days to Date
Given a date in YYYY-MM-DD format and an integer number of days, return the resulting date in the same format.
Weekday from date
Write a function that returns the full English weekday name for a date string.
Leap Years in Range
Write a function that returns a list of all leap years between two given years, inclusive.
Age in years months days
Given birth and reference dates, return age as a dictionary with years, months, days.
Time Difference HH:MM
Given two times in HH:MM format, return the absolute difference as a string in HH:MM format.
Unix timestamp to datetime
Write a function that returns a UTC datetime string from a Unix timestamp.
Next Weekday Finder
Write a function that returns the next weekday date after a given date.
Showing 313–336 of 371 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.