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###### tags: `Leetcode`

# 1071. Greatest Common Divisor of Strings

###### Link : https://leetcode.com/problems/greatest-common-divisor-of-strings/description/

## 題目
回傳GCD of Strings
**GCD of Strings:
t divides s" if and only if s = t + ... + t**
## 程式碼

class Solution {
public:
    string gcdOfStrings(string str1, string str2) {
        string ans, temp;
        const int size1 = str1.size(), size2 = str2.size();
        for(int i = 0;i < size2;i++){
            temp += str2[i];
            if(isDivisor(str1, temp) && isDivisor(str2, temp) && temp.size() > ans.size())
                ans = temp;
        }
        return ans;
    }
    bool isDivisor(string &str, string &sub){
        const int strSize = str.size(), subSize = sub.size();
        if(strSize % subSize != 0) return false;
        int i =0, j = 0;
        while(i < strSize){
            if(str[i] != sub[j]) return false;
            ++i, ++j;
            if(j >= subSize) j = 0;
        }
        return true;
    }
};

## Date
### 2023/2/1