Amicable Numbers Check
Write a function that checks if two numbers are an amicable pair by comparing sums of proper divisors.
Armstrong Number Check
Implement a function that checks if a given integer is an Armstrong number.
Happy number check
Implement a function that returns True if a number is happy, False otherwise.
Harshad Number Check
Write a function that checks if a number is a Harshad (or Niven) number.
Smith Number Check
Write a function to check if a number is a Smith number by comparing digit sums of the number and its prime factorization.
Triangular Number
Implement a function that returns the nth triangular number using the closed-form formula.
Pentagonal Number
Given a positive integer n, return the nth pentagonal number using the formula P(n) = n(3n - 1)/2.
Lucas Sequence
Implement a function to compute the n-th Lucas number using iteration or recursion with memoization.
Partition function
Write a function that returns the number of ways to write a positive integer as a sum of positive integers (order irrelevant).
Extended Euclidean Algorithm
Implement the extended Euclidean algorithm to return (gcd, x, y) such that ax + by = gcd(a, b).
Deficient Number Check
Write is_deficient(n) that returns True if the sum of proper divisors is less than n.
Kaprekar number check
Check whether a given non-negative integer is a Kaprekar number in base 10.
Stars and Bars Count
Implement stars_and_bars_count(n, k) which returns the number of ways to put n identical items into k distinct bins, with bins allowed to be empty.
Correlation Coefficient
Write a pure-Python function that computes the Pearson correlation coefficient between two lists of numbers.
Z score normalization
Compute the z-scores for a list of numbers using the population standard deviation.
Count Set Bits
Implement a function that returns the number of set bits (1s) in the binary representation of a non-negative integer.
Single Number XOR
Given a non-empty list of integers where every element appears twice except one, return the single number using XOR.
Missing Number XOR
Given a list of n distinct numbers from 0 to n with one missing, use XOR to find and return the missing number.
Isolate Rightmost Set Bit
Given an integer, return a number with only its rightmost set bit set.
Rotate Bits Left
Implement a function that rotates the bits of an integer to the left by a specified number of positions.
Bitwise AND of a Range
Given a range [a, b], return the bitwise AND of all integers in that inclusive range without iterating over all numbers.
Sparse Number Check
Check if a non-negative integer is sparse, meaning its binary representation contains no adjacent 1 bits.
Maximum XOR Pair
Implement max_xor_pair(nums) that returns the maximum XOR value obtainable by pairing any two numbers in the given list.
Odd Parity Bit
Given an integer, return the odd parity bit (0 or 1) so that total number of 1-bits in the 8-bit representation becomes odd.
Showing 97–120 of 184 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.