Sync LeetCode submission Runtime - 39 ms (5.00%), Memory - 17.3 MB (92.98%)

Author: koralkulacoglu

LeetCode/0085-maximal-rectangle/README.md

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+<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;= rows, 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>

LeetCode/0085-maximal-rectangle/solution.cpp

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+class Solution {
+public:
+    int maximalRectangle(vector<vector<char>>& matrix) {
+        int n = matrix.size();
+        int m = matrix[0].size();
+
+        vector<vector<int>> ones(n, vector<int>(m, 0));
+        for (int i=0; i<n; i++) {
+            ones[i][0] = matrix[i][0] - '0';
+            for (int j=1; j<m; j++) ones[i][j] = (matrix[i][j] == '1' ? ones[i][j-1] + 1 : 0);
+        }
+
+        int ans = 0;
+        for (int i=0; i<n; i++) {
+            for (int j=0; j<m; j++) {
+                int width = 1e9;
+                int height = 0;
+                for (int k=i; k>=0; k--) {
+                    height++;
+                    width = min(width, ones[k][j]);
+                    ans = max(ans, height * width);
+                }
+            }
+        }
+        
+        return ans;
+    }
+};