The key challenge to this problem is to make the code clean. has shared a nice example, which is rewritten below in C++.

class Solution {public:    string convert(string s, int numRows) {        vector
     
       vs(numRows, "");        int n = s.length(), i = 0;        while (i < n) {            for (int j = 0; j < numRows && i < n; j++)                vs[j].push_back(s[i++]);            for (int j = numRows - 2; j >= 1 && i < n; j--)                vs[j].push_back(s[i++]);        }        string zigzag;        for (string v : vs) zigzag += v;        return zigzag;    } };