class Solution {
public:
    string longestCommonPrefix(vector<string>& strs) {
        string res;
        if (strs.empty()) return res;

        // 从第一个字符开始枚举
        for (int i = 0; ; i ++)
        {
            if(i >= strs[0].size()) return res;
            char c = strs[0][i];
            for (auto& str : strs)
            {
                if (i >= str.size() || str[i] != c)
                    return res;
            }
            res += c;
        }
        return res;
    }
};