<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:
    def convert(self, s: str, numRows: int) -> str:
        if (numRows == len(s) or numRows == 1 ): return s
        matrix = [[0]*((len(s)//2) + 1) for i in range(numRows)]
        r, c = 0, 0
        st = list(s)
        cnt = 0
        while cnt != len(s):
            for r in range(0, numRows):
                if cnt == len(s):
                    break
                matrix[r][c] = st[cnt]
                cnt += 1
            
            c += 1
            for r in range(numRows-2, 0, -1):
                if cnt == len(s):
                    break
                matrix[r][c] = st[cnt]

                c += 1
                cnt += 1
        ans = ''
        for r in range(len(matrix)):
            for c in range(len(matrix[0])):
                if matrix[r][c] != 0:
                    ans += matrix[r][c]
        return ans

20000