# 6: ZigZag Conversion (Medium)
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
# Solution:
```javascript
/**
* @param {string} s
* @param {number} numRows
* @return {string}
*/
var convert = function (inputString, targetRows) {
if (targetRows == 1) {
return inputString;
}
// Start the process on row 1, heading down
let currentRow = 1;
let headingDown = true;
// Initialise an array to store the zigzag data
let zigZagArray = [];
// Loop through the requested number of rows
for (let i = 0; i < targetRows; i++) {
// Initialise each zigzag row as an empty array
zigZagArray[i] = [];
}
// Loop through the string
for (let i = 0; i < inputString.length; i++) {
// Add the current letter to the current row
zigZagArray[currentRow - 1].push(inputString[i]);
if (headingDown) {
currentRow++;
// Check if we've exceeded the maximum number of rows
if (currentRow > targetRows) {
// Start heading back up again
currentRow = targetRows - 1;
headingDown = false;
}
} else {
currentRow--;
// Check if we've exceeded the top row
if (currentRow < 1) {
// Start heading down again
currentRow = 2;
headingDown = true;
}
}
}
// Initialise a return string
let totalString = '';
// Loop through the constructed rows
for (let i = 0; i < targetRows; i++) {
// Append the row's characters joined together
totalString += zigZagArray[i].join('');
}
return totalString;
};
```
# Explanation: