<p>The string <code>&quot;PAYPALISHIRING&quot;</code> 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>

<pre>
P   A   H   N
A P L S I I G
Y   I   R
</pre>

<p>And then read line by line: <code>&quot;PAHNAPLSIIGYIR&quot;</code></p>

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

<pre>
string convert(string s, int numRows);
</pre>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;PAYPALISHIRING&quot;, numRows = 3
<strong>Output:</strong> &quot;PAHNAPLSIIGYIR&quot;
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;PAYPALISHIRING&quot;, numRows = 4
<strong>Output:</strong> &quot;PINALSIGYAHRPI&quot;
<strong>Explanation:</strong>
P     I    N
A   L S  I G
Y A   H R
P     I
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;A&quot;, numRows = 1
<strong>Output:</strong> &quot;A&quot;
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= s.length &lt;= 1000</code></li>
	<li><code>s</code> consists of English letters (lower-case and upper-case), <code>&#39;,&#39;</code> and <code>&#39;.&#39;</code>.</li>
	<li><code>1 &lt;= numRows &lt;= 1000</code></li>
</ul>

class Solution {
public:
    string convert(string s, int numRows) {
        if(numRows == 1 || s.size() <= numRows) return s;

        // Calculate Columns
        int zigzagNums = (s.size() / (2*numRows-2))+1;
        int numCols = zigzagNums*(numRows-1);
        vector<vector<char>> zigzag = vector<vector<char>>(numRows, vector<char>(numCols, 0));

        // cout << zigzagNums << endl;
        // cout << numCols << endl;

        bool goingDown = true;
        int row = 0; int col = 0;
        for(int i = 0; i < s.size(); i++) {
            // cout << row << ", " << col << endl;
            zigzag[row][col] = s[i];
            if(goingDown) {
                // Stop going down
                if(row == numRows-1) {
                    goingDown = false;
                    row--; col++;
                }
                // Going down
                else {
                    row++;
                }
            } else {
                // Stop going up
                if(row == 0) {
                    goingDown = true;
                    row++;
                } 
                // Going up
                else {
                    row--; col++;
                }
            }
        }

        int s_Index = 0;
        for(int i = 0; i < numRows; i++) {
            for(int j = 0; j < numCols; j++) {
                if(zigzag[i][j] != 0){
                    s[s_Index] = zigzag[i][j];
                    s_Index++;
                } 
            }
        }
        return s;
    }
};
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