DAY 45 OF 90 · Know when to stop

Greatest common divisor

Medium90 Days of Looping

Inputs

a and b are whole numbers from 1 to 500.

Your tasks

Use a while loop that runs while b is not 0.
Each round, replace a with b, and b with the remainder of the old a divided by the old b.
Complete gcd so it returns a. Return it, do not print it.

Example

With a = 48 and b = 18, gcd returns 6.

Rules

Both inputs are at least 1.

Test data

TEST DATA 1: a is 48, b is 18

TEST DATA 2: a is 7, b is 13

Practice focus

While loops and early exits, for when you don't know how many rounds you need. Binary search, the Euclidean algorithm and graph search are all while loops with a clear stopping rule.

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