Zigzag Conversion Leetcode Solution

In this post, you will know how to solve the Zigzag Conversion Leetcode Solution problem of Leetcode. This Leetcode problem is done in many programming languages like C++, Java, and Python.

Zigzag Conversion Leetcode Solution
Zigzag Conversion Leetcode Solutions

One more thing to add, don’t directly look for the solutions, first try to solve the problems of Leetcode by yourself. If you find any difficulty after trying several times, then you can look for solutions.


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
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

Example 2:

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

Example 3:

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


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

 Zigzag Conversion Leetcode Solutions in Python

class Solution(object):
    def convert(self, s, numRows):
        :type s: str
        :type numRows: int
        :rtype: str
        if numRows == 1 or numRows >= len(s):
            return s
        L = [''] * numRows
        index, step = 0, 1
        for x in s:
            L[index] += x
            if index == 0:
                step = 1
            elif index == numRows -1:
                step = -1
            index += step
        return ''.join(L)

 Zigzag Conversion Leetcode Solutions in CPP

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

Zigzag Conversion Leetcode Solutions in Java

class Solution {
    public String convert(String s, int nRows) {
        char[] c = s.toCharArray();
        int len = c.length;
        StringBuffer[] sb = new StringBuffer[nRows];
        for (int i = 0; i < sb.length; i++) sb[i] = new StringBuffer();
        int i = 0;
        while (i < len) {
            for (int idx = 0; idx < nRows && i < len; idx++) // vertically down
            for (int idx = nRows-2; idx >= 1 && i < len; idx--) // obliquely up
        for (int idx = 1; idx < sb.length; idx++)
        return sb[0].toString();

Note: This problem Zigzag Conversion is generated by Leetcode but the solution is provided by BrokenProgrammers. This tutorial is only for Educational and Learning purposes.

NEXT: Longest Palindromic Substring Leetcode Solution

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