ZigZag Conversion

string convert(string s, int numRows) {    vector<string> temp(numRows);    if (numRows == 1) return s;    int flag = 1;    int count = 0;    for (int i = 0; i < s.size(); i++) {        if (count == 0) flag = 1;        else if (count == numRows - 1) flag = -1;        temp[count] += s[i];        count += flag;    }    string res;    for (int i = 0; i < temp.size(); i++) {        res += temp[i];    }    return res;}