Zigzag Conversion Solution in C++ | LeetCode

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The string "PAYPALISHIRING" is written in a zigzag pattern on a given number of rows like this: (you may want to display this pattern in a fixed font for better legibility)

P   A   H   N
A P L S I I G
Y   I   R

And then read line by line: "PAHNAPLSIIGYIR"

Write the code that will take a string and make this conversion given a number of rows:

string convert(string s, int numRows);

Example 1:

Input: s = "PAYPALISHIRING", numRows = 3
Output: "PAHNAPLSIIGYIR"

Example 2:

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

Example 3:

Input: s = "A", numRows = 1
Output: "A"

Constraints:

• 1 <= s.length <= 1000
• s consists of English letters (lower-case and upper-case), ',' and '.'.
• 1 <= numRows <= 1000

Code in C++

class Solution {
public:
   string convert(string s, int numRows) {
    if (numRows == 1) return s;
    string result;
    int n = s.size();
    int cycle = 2 * numRows - 2;
    for (int i = 0; i < numRows; i++) {
        for (int j = 0; j + i < n; j += cycle) {
            result += s[j + i];
            if (i != 0 && i != numRows - 1 && j + cycle - i < n)
                result += s[j + cycle - i];
        }
    }
    return result;
}

};