<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)
    {
        vector<ostringstream> lines(numRows);
        int row = 0;
        bool directionIsDown = true;
        for (char &c : s)
        {
            
#ifdef DEBUG
            if (row != 0 && !directionIsDown)
            {
                for (int i = 0; i < numRows; i++)
                {
                    if (i != row)
                    {
                        lines[i] << ' ';
                    }
                    lines[i] << ' ';
                }
            }
#endif
            lines[row] << c;

            if (directionIsDown)
            {
                if (row == numRows - 1)
                {
                    directionIsDown = false;
                    --row;
                }
                else
                {
                    ++row;
                }
            }
            else
            {
                if (row == 0)
                {
                    directionIsDown = true;
                    ++row;
                }
                else
                {
                    --row;
                }
            }
            row = row % numRows;
        }
        ostringstream output;
        for (ostringstream &line : lines)
        {
            string str = line.str();
            cout << str << std::endl;
            output << str;
        }
        return output.str();
    }
};
36931