6. Z 字形变换(c++)

class Solution {
public:
    string convert(string s, int numRows) {
        if(numRows == 1){
            return s;
        }
        vectorres(numRows);//res的大小为非空行数大小
        int i = 0;
        int flag = -1;
        for(char c:s){
            res[i] += c;
            if(i == 0 || i == numRows -1){
                flag = -flag;//行数逆转
            }
            i += flag;
        }
        string new_s;
        for(string r:res){
            new_s += r;
        }
        return new_s;
    }
};

参考链接：
https://leetcode-cn.com/problems/zigzag-conversion/solution/zzi-xing-bian-huan-by-jyd/