2264. Largest 3-Same-Digit Number in String

class Solution {
public:
    string largestGoodInteger(string num) {
        string max = "";
        string match = "";

        for(int i=2; i<num.length(); i++)
        {
            if(num[i-1] == num[i-2] && num[i] == num[i-2])
            {
                match += num[i];
                match += num[i];
                match += num[i];
            }
            

            if(match.length()==3)
            {
                if(max.length()==0)
                {
                    max = match;
                }
                else if(max[0]-'0' < match[0]-'0')
                {
                    max = match;
                }

                match = "";
            }


        }

        return max;
    }
};