Greatest Common Divisor of Strings

Difficulty

Easy

Question

For two strings s and t, we say "`t` divides `s`" if and only if s = t + ... + t (t concatenated with itself 1 or more times)

Given two strings str1 and str2, return the largest string x such that x divides both str1 and str2.

Example:

Input: str1 = "ABCABC", str2 = "ABC"
Output: "ABC"

Link

Greatest Common Divisor of Strings