<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 < 2:
            return s
        
        per_cycle = numRows + (numRows - 2)
        
        total_cycles = len(s) // per_cycle
        remaining_chars = len(s) % per_cycle
        
        if remaining_chars > 0:
            extra_cols = (remaining_chars if remaining_chars <= numRows 
                          else remaining_chars - numRows + 1)
        else:
            extra_cols = 0
        
        cols = total_cycles * (numRows - 1) + extra_cols

        grid = [[' ' for _ in range(cols)] for _ in range(numRows)]

        i = 0
        r = c = 0 

        while i < len(s):
            
            for down in range(numRows):
                if i >= len(s):  
                    break
                grid[r][c] = s[i]
                r += 1
                i += 1
            
            r -= 2
            c += 1

            for diag in range(numRows - 2):
                if i >= len(s): 
                    break
                grid[r][c] = s[i]
                r -= 1
                c += 1
                i += 1
            

            r = 0

        output = ''
        for row in grid:
            output += ''.join(filter(lambda x: x != ' ', row))


        return output

19300