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Python coding challenges
226 challenges you can solve in Python, from first loops to graphs, dynamic programming and machine learning. Write your code in the browser, run the tests instantly and get an AI review.
Easy · 134 Medium · 68 Hard · 24
Skills you'll practise: CountingDigit extractionString splitting2D listsArithmeticFormulasListsLoopsConditionsDivisibilityFloating pointGradient descent
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- 226
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All challenges
Search by topic, language, or difficulty.
Hard
Mini Stack-Language Interpreter
Evaluate a small stack language.
You'll learn
TokenizingExecuting instructions
No solutions yet
Hard
Count Inversions
Count the out-of-order pairs in a list.
You'll learn
Merge sortDivide and conquer
No solutions yet
Hard
Trapping Rain Water
Compute how much rain water an elevation map holds.
You'll learn
Two pointersPrefix maxima
No solutions yet
Medium
Island Perimeter
Measure the coastline of land cells in a grid.
You'll learn
Edge counting4-neighbor checks
No solutions yet
Easy
Pyramid Rows
Draw a right-aligned pyramid of # blocks.
You'll learn
String patternsPadding
No solutions yet
Easy
Rectangle Perimeter
Compute the perimeter of a rectangle from its sides.
You'll learn
ArithmeticReturn values
Hard
Sliding Window Maximum
Report the maximum of every window of k numbers.
You'll learn
Monotonic dequeO(n) windows
No solutions yet
Easy
Hollow Square
Draw the outline of a square with * characters.
You'll learn
Edge detectionBuilding strings
No solutions yet
Medium
Recursive Palindrome
Check a palindrome recursively, ignoring case and punctuation.
You'll learn
Base casesString cleaning
No solutions yet
Easy
Days in a Month
Return how many days a month has, including leap years.
You'll learn
Calendar rulesHelper functions
No solutions yet
Easy
Celsius to Fahrenheit
Convert a temperature from Celsius to Fahrenheit.
You'll learn
FormulasOperator precedence
No solutions yet
Easy
Cash: Fewest Coins
Give change with as few U.S. coins as possible.
You'll learn
Greedy algorithmsCoin change
No solutions yet
Medium
Tic-Tac-Toe Winner
Decide the result of a tic-tac-toe board.
You'll learn
Win conditionsDiagonals
No solutions yet
Easy
Fibonacci Number
Return the n-th Fibonacci number.
You'll learn
IterationUpdating two variables
No solutions yet
Medium
Find Right-Triangle Triples
List all integer right triangles with a specified perimeter.
You'll learn
EnumerationAvoiding duplicates
No solutions yet
Hard
Matrix Chain Multiplication
Find the cheapest order to multiply a chain of matrices.
You'll learn
Interval DPOptimization
No solutions yet
Medium
Count Grid Paths
Count routes across a rectangular grid using only right and down moves.
You'll learn
Grid path countingBinomial coefficients
No solutions yet
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