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 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: ""
Example 4:
Input: str1 = "ABCDEF", str2 = "ABC" Output: ""
Constraints:
1 <= str1.length <= 10001 <= str2.length <= 1000str1 and str2 consist of English uppercase letters.struct Solution;
impl Solution {
fn gcd_of_strings(str1: String, str2: String) -> String {
let n1 = str1.len();
let n2 = str2.len();
let mut n = usize::min(n1, n2);
while n > 0 {
if n1 % n != 0 || n2 % n != 0 {
n -= 1;
continue;
}
let s1 = &str1[0..n];
let s2 = &str2[0..n];
if s1 != s2 {
n -= 1;
continue;
}
let k1 = n1 / n;
let k2 = n2 / n;
if str1.matches(s1).count() == k1 && str2.matches(s2).count() == k2 {
return s1.to_string();
}
n -= 1;
}
"".to_string()
}
}
#[test]
fn test() {
let str1 = "ABCABC".to_string();
let str2 = "ABC".to_string();
let res = "ABC".to_string();
assert_eq!(Solution::gcd_of_strings(str1, str2), res);
let str1 = "ABABAB".to_string();
let str2 = "ABAB".to_string();
let res = "AB".to_string();
assert_eq!(Solution::gcd_of_strings(str1, str2), res);
let str1 = "LEET".to_string();
let str2 = "CODE".to_string();
let res = "".to_string();
assert_eq!(Solution::gcd_of_strings(str1, str2), res);
}