day1

C++ 代码

class Solution {
public:
    string largestGoodInteger(string num) {
        string res; //默认res = "";
        for (int i = 0; i < num.size() - 2; i ++ ) //防止越界
        {
            if (num[i] == num[i + 1] && num[i + 1] == num[i + 2]) 
            {
                res = max(res, num.substr(i, 3)); //max函数也可以直接比较string对象
            }
        }
        return res;
    }
};