_{[1071 - Greatest Common Divisor of Strings](https://leetcode.com/problems/greatest-common-divisor-of-strings/)} | _{<div align='center'>❌</div>} | _{<div align='center'>❌</div>} | _{<div align='center'>[✔️](cpp%2F1071-greatest-common-divisor-of-strings.cpp)</div>} | _{<div align='center'>❌</div>} | _{<div align='center'>❌</div>} | _{<div align='center'>[✔️](go%2F1071-greatest-common-divisor-of-strings.go)</div>} | _{<div align='center'>❌</div>} | _{<div align='center'>[✔️](java%2F1071-greatest-common-divisor-of-strings.java)</div>} | _{<div align='center'>[✔️](javascript%2F1071-greatest-common-divisor-of-strings.js)</div>} | _{<div align='center'>[✔️](kotlin%2F1071-greatest-common-divisor-of-strings.kt)</div>} | _{<div align='center'>[✔️](python%2F1071-greatest-common-divisor-of-strings.py)</div>} | _{<div align='center'>❌</div>} | _{<div align='center'>[✔️](rust%2F1071-greatest-common-divisor-of-strings.rs)</div>} | _{<div align='center'>❌</div>} | _{<div align='center'>❌</div>} | _{<div align='center'>[✔️](typescript%2F1071-greatest-common-divisor-of-strings.ts)</div>}

class Solution:

def gcdOfStrings(self, str1: str, str2: str) -> str:

len1, len2 = len(str1), len(str2)

def valid(k):

if len1 % k or len2 % k:

return False

n1, n2 = len1 // k, len2 // k

base = str1[:k]

return str1 == n1 * base and str2 == n2 * base

for i in range(min(len1, len2), 0, -1):

if valid(i):

return str1[:i]

return ""