<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 len(s) == 1 or numRows==1:
            return s
        
        # calculate numCols
        numCols = 0
        i = 0
        while i < len(s):
            print(numCols, i)
            if i%(numRows-1) == 0:
                i += numRows
                numCols += 1 # one column gets added when all rows are filled
            else:
                i += 1
                numCols += 1 # numRows - 2 columns get added for zig-zag

        # add elements and white spaces to array
        new_arr = [[] for cols in range(numCols)]
        cols = 0
        i = 0
        j = 0
        while i < len(s) and cols < numCols:
            if cols % (numRows-1) == 0:
                j = 0
                new_arr[cols] += list(s[i:i+numRows])
                i += numRows
            else:
                j+=1
                new_arr[cols] += [" "]*(numRows-j-1)
                new_arr[cols].append(s[i])
                new_arr[cols] += [" "]*(j)
                i += 1
            cols += 1
        if len(new_arr[-1]) < numRows:
            new_arr[-1] += [" "]*(numRows-len(new_arr[-1]))
        
        # convert array to string
        final_string = ""
        transpose = list(zip(*new_arr))
        for row in transpose:
            final_string += "".join(row)
        return final_string.replace(" ","")

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