<p>Given a <code>rows x cols</code>&nbsp;binary <code>matrix</code> filled with <code>0</code>&#39;s and <code>1</code>&#39;s, find the largest rectangle containing only <code>1</code>&#39;s and return <em>its area</em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2020/09/14/maximal.jpg" style="width: 402px; height: 322px;" />
<pre>
<strong>Input:</strong> matrix = [[&quot;1&quot;,&quot;0&quot;,&quot;1&quot;,&quot;0&quot;,&quot;0&quot;],[&quot;1&quot;,&quot;0&quot;,&quot;1&quot;,&quot;1&quot;,&quot;1&quot;],[&quot;1&quot;,&quot;1&quot;,&quot;1&quot;,&quot;1&quot;,&quot;1&quot;],[&quot;1&quot;,&quot;0&quot;,&quot;0&quot;,&quot;1&quot;,&quot;0&quot;]]
<strong>Output:</strong> 6
<strong>Explanation:</strong> The maximal rectangle is shown in the above picture.
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> matrix = [[&quot;0&quot;]]
<strong>Output:</strong> 0
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> matrix = [[&quot;1&quot;]]
<strong>Output:</strong> 1
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>rows == matrix.length</code></li>
	<li><code>cols == matrix[i].length</code></li>
	<li><code>1 &lt;= row, cols &lt;= 200</code></li>
	<li><code>matrix[i][j]</code> is <code>&#39;0&#39;</code> or <code>&#39;1&#39;</code>.</li>
</ul>

class Solution:
    def maximalRectangle(self, matrix: List[List[str]]) -> int:
        rows = len(matrix)
        columns = len(matrix[0])
        maxArea = 0

        for i in range(rows) :
            for j in range(columns) :
                matrix[i][j] = ord(matrix[i][j]) - ord('0')

        for i in range(rows) :
            for j in range(columns-2, -1, -1) :
                if matrix[i][j] == 1 :
                    matrix[i][j] += matrix[i][j+1]
        
        print(matrix)
        curMax = []
        for j in range(columns) :
            for i in range(rows) :
                print(i,j, maxArea, curMax)
                if(matrix[i][j] != 0) :
                    lowest = i
                    while(len(curMax) != 0) :
                        if(curMax[0][0] < -matrix[i][j]) :
                            val = heappop(curMax)
                            maxArea = max(maxArea, -val[0]*(i - val[1]))
                            lowest = val[1]
                        else :
                            break
                    if(not (len(curMax) !=0 and curMax[0][0] == -matrix[i][j])) :
                        heappush(curMax, (-matrix[i][j], lowest))
                else :
                    while(len(curMax) !=0) :
                        val = heappop(curMax)
                        maxArea = max(maxArea, -val[0]*(i - val[1]))
                print(curMax)
            while(len(curMax) !=0) :
                val = heappop(curMax)
                maxArea = max(maxArea, -val[0]*(i - val[1] + 1))
        while(len(curMax) !=0) :
            val = heappop(curMax)
            maxArea = max(maxArea, -val[0]*(i - val[1] + 1))
        
        return maxArea
18200