1071. Greatest Common Divisor of Strings

Posted on Edited on In

1071. Greatest Common Divisor of Strings

Description

Difficulty: Easy

Related Topics: Math, String

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:

1
2
Input: str1 = "ABCABC", str2 = "ABC"
Output: "ABC"

Example 2:

1
2
Input: str1 = "ABABAB", str2 = "ABAB"
Output: "AB"

Example 3:

1
2
Input: str1 = "LEET", str2 = "CODE"
Output: ""

Constraints:

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

Hints/Notes

  • Think about it methmatically, like str1 is k subStrings and str2 is l subStrings

Solution

Language: C++

1
2
3
4
5
6
7
8
9
10
class Solution {
public:
    string gcdOfStrings(string str1, string str2) {
        if (str1 + str2 != str2 + str1) {
            return "";
        }
        int gcdLength = gcd(str1.size(), str2.size());
        return str1.substr(0, gcdLength);
    }
};