<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>

import math 

class Solution:
    def convert(self, s: str, numRows: int) -> str:
        # Row 1 indices: 0, numRows*2-2, numRows*4-4 + ...
        # Row 2 indices: 1, 1+
        if numRows == 1: 
            return s

        s_len = len(s)
        size = int(0.8*(s_len)) + 1
        a = [['' for _ in range(size)] for _ in range(numRows)]
        i = 0
        curr_col = 0
        while i < s_len:
            mod = curr_col % (numRows-1)
            if mod == 0:
                k = 0
                while k < numRows and i+k<s_len:
                    a[k][curr_col] = s[i+k]
                    k += 1
                i += numRows
            else: 
                a[numRows-1-mod][curr_col] = s[i]
                i += 1
            curr_col += 1
        ret_str = ''
        for i in range(numRows):
            ret_str += ''.join(a[i])
        return ret_str



        
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