85:最大矩形

src/main/java/leetcode/editor/cn/MaximalRectangle.java

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+//给定一个仅包含 0 和 1 、大小为 rows x cols 的二维二进制矩阵，找出只包含 1 的最大矩形，并返回其面积。 
+//
+// 
+//
+// 示例 1： 
+//
+// 
+//输入：matrix = [["1","0","1","0","0"],["1","0","1","1","1"],["1","1","1","1","1"]
+//,["1","0","0","1","0"]]
+//输出：6
+//解释：最大矩形如上图所示。
+// 
+//
+// 示例 2： 
+//
+// 
+//输入：matrix = []
+//输出：0
+// 
+//
+// 示例 3： 
+//
+// 
+//输入：matrix = [["0"]]
+//输出：0
+// 
+//
+// 示例 4： 
+//
+// 
+//输入：matrix = [["1"]]
+//输出：1
+// 
+//
+// 示例 5： 
+//
+// 
+//输入：matrix = [["0","0"]]
+//输出：0
+// 
+//
+// 
+//
+// 提示： 
+//
+// 
+// rows == matrix.length 
+// cols == matrix[0].length 
+// 0 <= row, cols <= 200 
+// matrix[i][j] 为 '0' 或 '1' 
+// 
+// Related Topics 栈 数组 哈希表 动态规划 
+// 👍 935 👎 0
+
+package leetcode.editor.cn;
+
+//85:最大矩形
+public class MaximalRectangle {
+    public static void main(String[] args) {
+        //测试代码
+        Solution solution = new MaximalRectangle().new Solution();
+    }
+
+    //力扣代码
+    //leetcode submit region begin(Prohibit modification and deletion)
+    class Solution {
+        public int maximalRectangle(char[][] matrix) {
+            int m = matrix.length;
+            if (m == 0) {
+                return 0;
+            }
+            int n = matrix[0].length;
+            int[][] left = new int[m][n];
+
+            for (int i = 0; i < m; i++) {
+                for (int j = 0; j < n; j++) {
+                    if (matrix[i][j] == '1') {
+                        left[i][j] = (j == 0 ? 0 : left[i][j - 1]) + 1;
+                    }
+                }
+            }
+
+            int ret = 0;
+            for (int i = 0; i < m; i++) {
+                for (int j = 0; j < n; j++) {
+                    if (matrix[i][j] == '0') {
+                        continue;
+                    }
+                    int width = left[i][j];
+                    int area = left[i][j];
+                    for (int k = i - 1; k >= 0; k--) {
+                        width = Math.min(width, left[k][j]);
+                        area = Math.max(area, (i - k + 1) * width);
+                    }
+                    ret = Math.max(ret, area);
+                }
+            }
+            return ret;
+        }
+    }
+//leetcode submit region end(Prohibit modification and deletion)
+
+}

src/main/java/leetcode/editor/cn/MaximalRectangle.md

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+<p>给定一个仅包含 <code>0</code> 和 <code>1</code> 、大小为 <code>rows x cols</code> 的二维二进制矩阵，找出只包含 <code>1</code> 的最大矩形，并返回其面积。</p>
+
+<p> </p>
+
+<p><strong>示例 1：</strong></p>
+<img alt="" src="https://assets.leetcode.com/uploads/2020/09/14/maximal.jpg" style="width: 402px; height: 322px;" />
+<pre>
+<strong>输入：</strong>matrix = [["1","0","1","0","0"],["1","0","1","1","1"],["1","1","1","1","1"],["1","0","0","1","0"]]
+<strong>输出：</strong>6
+<strong>解释：</strong>最大矩形如上图所示。
+</pre>
+
+<p><strong>示例 2：</strong></p>
+
+<pre>
+<strong>输入：</strong>matrix = []
+<strong>输出：</strong>0
+</pre>
+
+<p><strong>示例 3：</strong></p>
+
+<pre>
+<strong>输入：</strong>matrix = [["0"]]
+<strong>输出：</strong>0
+</pre>
+
+<p><strong>示例 4：</strong></p>
+
+<pre>
+<strong>输入：</strong>matrix = [["1"]]
+<strong>输出：</strong>1
+</pre>
+
+<p><strong>示例 5：</strong></p>
+
+<pre>
+<strong>输入：</strong>matrix = [["0","0"]]
+<strong>输出：</strong>0
+</pre>
+
+<p> </p>
+
+<p><strong>提示：</strong></p>
+
+<ul>
+	<li><code>rows == matrix.length</code></li>
+	<li><code>cols == matrix[0].length</code></li>
+	<li><code>0 <= row, cols <= 200</code></li>
+	<li><code>matrix[i][j]</code> 为 <code>'0'</code> 或 <code>'1'</code></li>
+</ul>
+<div><div>Related Topics</div><div><li>栈</li><li>数组</li><li>哈希表</li><li>动态规划</li></div></div>\n<div><li>👍 935</li><li>👎 0</li></div>