Zigzag Conversion

Fri, 16 Oct 2026 22:22:53 +0700

Example:

Input: s = "PAYPALISHIRING", numRows = 4
Output: "PINALSIGYAHRPI"
Explanation:
P I N
A L S I G
Y A H R
P I

class Solution {
public:
 string convert(string s, int numRows) {
 if (numRows == 1) {
 return s;
 }

 int cycle = (numRows - 1) * 2;
 string result = "";
 for (int row = 0; row < numRows; row++) {
 for(int i = row; i < s.size(); i+=cycle) {
 result += s[i];
 int diag = i + cycle - 2 * row;
 if (row != 0 && row != numRows - 1 && diag < s.size()) {
 result += s[diag];
 }
 }
 }

 return result;
 }
};

Leetcode on Today I Learned - Saugi

Zigzag Conversion