Prime Factorization
Return a sorted list of prime factors of a positive integer, including repeated factors.
Count divisors
Compute the number of positive divisors of a given integer using its prime factorization.
Sum of divisors
Given an integer n, return the sum of all its positive divisors.
Abundant Number Check
Implement a function to check whether a given integer is abundant: sum of proper divisors exceeds the number.
Armstrong Number Check
Implement a function that checks if a given integer is an Armstrong number.
Pentagonal Number
Given a positive integer n, return the nth pentagonal number using the formula P(n) = n(3n - 1)/2.
Partition function
Write a function that returns the number of ways to write a positive integer as a sum of positive integers (order irrelevant).
Multiply without multiply
Write a function that multiplies two integers using only addition, subtraction, and bit shifts — no * operator.
Integer Square Root
Implement integer_sqrt(n) that returns the largest integer whose square is ≤ n.
Kaprekar number check
Check whether a given non-negative integer is a Kaprekar number in base 10.
Multinomial coefficient
Write a function to compute the multinomial coefficient efficiently for given nonnegative counts.
Count Set Bits
Implement a function that returns the number of set bits (1s) in the binary representation of a non-negative integer.
Check Power of Two Bits
Implement is_power_of_two(n) that returns True if n is a power of two and False otherwise.
Single Number XOR
Given a non-empty list of integers where every element appears twice except one, return the single number using XOR.
Gray Code Encode
Implement a function that converts a non-negative integer to its Gray code representation using bitwise XOR and shift.
Gray Code Decode
Implement gray_decode(n) that converts an n-bit Gray code integer back to its standard binary value using XOR accumulation.
Find Rightmost Set Bit
Implement a function that returns the 1-indexed position of the rightmost set bit of a positive integer, or 0 if none.
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.
Add without plus
Implement a function that adds two integers using only bitwise operations, no arithmetic plus or minus.
Divide using shifts
Implement division of two integers using only bit shifts and arithmetic, without using division or modulo operators.
Set kth Bit
Implement a function that sets the kth bit (0-indexed) of a non-negative integer to 1 and returns the result.
Clear kth Bit
Implement a function that clears the k-th bit of a non-negative integer (turns it to 0) using bitwise operations.
Showing 73–96 of 163 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.