Greatest common divisor of strings

class Solution:
    def gcdOfStrings(self, str1: str, str2: str) -> str:
                # Check if they have non-zero GCD string.
        if str1 + str2 != str2 + str1:
            return ""

        # Get the GCD of the two lengths.
        max_length = gcd(len(str1), len(str2))
        return str1[:max_length]

Greatest Common Divisor of Strings

Difficulty: Easy

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

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

 

Example 1:

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

Example 2:

Input: str1 = "ABABAB", str2 = "ABAB"
Output: "AB"

Example 3:

Input: str1 = "LEET", str2 = "CODE"
Output: ""

 

Constraints:

  • 1 <= str1.length, str2.length <= 1000
  • str1 and str2 consist of English uppercase letters.