+ problem 85

Author: fruit-in

Problemset/0085-Maximal Rectangle/README.md

@@ -0,0 +1,69 @@
+# 85. Maximal Rectangle
+Given a `rows x cols` binary `matrix` filled with `0`'s and `1`'s, find the largest rectangle containing only `1`'s and return *its area*.
+
+#### Example 1:
+![](https://assets.leetcode.com/uploads/2020/09/14/maximal.jpg)
+<pre>
+<strong>Input:</strong> matrix = [["1","0","1","0","0"],["1","0","1","1","1"],["1","1","1","1","1"],["1","0","0","1","0"]]
+<strong>Output:</strong> 6
+<strong>Explanation:</strong> The maximal rectangle is shown in the above picture.
+</pre>
+
+#### Example 2:
+<pre>
+<strong>Input:</strong> matrix = [["0"]]
+<strong>Output:</strong> 0
+</pre>
+
+#### Example 3:
+<pre>
+<strong>Input:</strong> matrix = [["1"]]
+<strong>Output:</strong> 1
+</pre>
+
+#### Constraints:
+* `rows == matrix.length`
+* `cols == matrix[i].length`
+* `1 <= row, cols <= 200`
+* `matrix[i][j]` is `'0'` or `'1'`.
+
+## Solutions (Rust)
+
+### 1. Solution
+```Rust
+impl Solution {
+    pub fn maximal_rectangle(matrix: Vec<Vec<char>>) -> i32 {
+        let rows = matrix.len();
+        let cols = matrix[0].len();
+        let mut prefix_sum = vec![vec![0; cols]; rows];
+        let mut ret = 0;
+
+        for r in 0..rows {
+            for c in 0..cols {
+                if matrix[r][c] == '0' {
+                    continue;
+                }
+
+                prefix_sum[r][c] = 1;
+
+                if c > 0 {
+                    prefix_sum[r][c] += prefix_sum[r][c - 1];
+                }
+
+                let mut min_w = i32::MAX;
+
+                for h in 1..=r + 1 {
+                    if prefix_sum[r + 1 - h][c] == 0 {
+                        break;
+                    }
+
+                    min_w = min_w.min(prefix_sum[r + 1 - h][c]);
+                    ret = ret.max(min_w * h as i32);
+                }
+            }
+        }
+
+        ret
+    }
+}
+```

Problemset/0085-Maximal Rectangle/README_CN.md

@@ -0,0 +1,69 @@
+# 85. 最大矩形
+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:
+![](https://assets.leetcode.com/uploads/2020/09/14/maximal.jpg)
+<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>
+
+#### 示例 2:
+<pre>
+<strong>输入:</strong> matrix = [["0"]]
+<strong>输出:</strong> 0
+</pre>
+
+#### 示例 3:
+<pre>
+<strong>输入:</strong> matrix = [["1"]]
+<strong>输出:</strong> 1
+</pre>
+
+#### 提示:
+* `rows == matrix.length`
+* `cols == matrix[i].length`
+* `1 <= row, cols <= 200`
+* `matrix[i][j]` 为 `'0'` 或 `'1'`
+
+## 题解 (Rust)
+
+### 1. 题解
+```Rust
+impl Solution {
+    pub fn maximal_rectangle(matrix: Vec<Vec<char>>) -> i32 {
+        let rows = matrix.len();
+        let cols = matrix[0].len();
+        let mut prefix_sum = vec![vec![0; cols]; rows];
+        let mut ret = 0;
+
+        for r in 0..rows {
+            for c in 0..cols {
+                if matrix[r][c] == '0' {
+                    continue;
+                }
+
+                prefix_sum[r][c] = 1;
+
+                if c > 0 {
+                    prefix_sum[r][c] += prefix_sum[r][c - 1];
+                }
+
+                let mut min_w = i32::MAX;
+
+                for h in 1..=r + 1 {
+                    if prefix_sum[r + 1 - h][c] == 0 {
+                        break;
+                    }
+
+                    min_w = min_w.min(prefix_sum[r + 1 - h][c]);
+                    ret = ret.max(min_w * h as i32);
+                }
+            }
+        }
+
+        ret
+    }
+}
+```

Problemset/0085-Maximal Rectangle/Solution.rs

@@ -0,0 +1,35 @@
+impl Solution {
+    pub fn maximal_rectangle(matrix: Vec<Vec<char>>) -> i32 {
+        let rows = matrix.len();
+        let cols = matrix[0].len();
+        let mut prefix_sum = vec![vec![0; cols]; rows];
+        let mut ret = 0;
+
+        for r in 0..rows {
+            for c in 0..cols {
+                if matrix[r][c] == '0' {
+                    continue;
+                }
+
+                prefix_sum[r][c] = 1;
+
+                if c > 0 {
+                    prefix_sum[r][c] += prefix_sum[r][c - 1];
+                }
+
+                let mut min_w = i32::MAX;
+
+                for h in 1..=r + 1 {
+                    if prefix_sum[r + 1 - h][c] == 0 {
+                        break;
+                    }
+
+                    min_w = min_w.min(prefix_sum[r + 1 - h][c]);
+                    ret = ret.max(min_w * h as i32);
+                }
+            }
+        }
+
+        ret
+    }
+}

README.md

@@ -68,6 +68,7 @@
 [81][81l]    |[Search in Rotated Sorted Array II][81]                                               |![rs]
 [82][82l]    |[Remove Duplicates from Sorted List II][82]                                           |![rb]
 [83][83l]    |[Remove Duplicates from Sorted List][83]                                              |![py]
+[85][85l]    |[Maximal Rectangle][85]                                                               |![rs]
 [86][86l]    |[Partition List][86]                                                                  |![py]
 [88][88l]    |[Merge Sorted Array][88]                                                              |![py]  ![rb]
 [89][89l]    |[Gray Code][89]                                                                       |![rs]
@@ -1399,6 +1400,7 @@
 [81]:Problemset/0081-Search%20in%20Rotated%20Sorted%20Array%20II/README.md#81-search-in-rotated-sorted-array-ii
 [82]:Problemset/0082-Remove%20Duplicates%20from%20Sorted%20List%20II/README.md#82-remove-duplicates-from-sorted-list-ii
 [83]:Problemset/0083-Remove%20Duplicates%20from%20Sorted%20List/README.md#83-remove-duplicates-from-sorted-list
+[85]:Problemset/0085-Maximal%20Rectangle/README.md#85-maximal-rectangle
 [86]:Problemset/0086-Partition%20List/README.md#86-partition-list
 [88]:Problemset/0088-Merge%20Sorted%20Array/README.md#88-merge-sorted-array
 [89]:Problemset/0089-Gray%20Code/README.md#89-gray-code
@@ -2723,6 +2725,7 @@
 [81l]:https://leetcode.com/problems/search-in-rotated-sorted-array-ii/
 [82l]:https://leetcode.com/problems/remove-duplicates-from-sorted-list-ii/
 [83l]:https://leetcode.com/problems/remove-duplicates-from-sorted-list/
+[85l]:https://leetcode.com/problems/maximal-rectangle/
 [84l]:https://leetcode.com/problems/largest-rectangle-in-histogram/
 [86l]:https://leetcode.com/problems/partition-list/
 [88l]:https://leetcode.com/problems/merge-sorted-array/

README_CN.md

@@ -68,6 +68,7 @@
 [81][81l]    |[搜索旋转排序数组 II][81]                                 |![rs]
 [82][82l]    |[删除排序链表中的重复元素 II][82]                         |![rb]
 [83][83l]    |[删除排序链表中的重复元素][83]                            |![py]
+[85][85l]    |[最大矩形][85]                                            |![rs]
 [86][86l]    |[分隔链表][86]                                            |![py]
 [88][88l]    |[合并两个有序数组][88]                                    |![py]  ![rb]
 [89][89l]    |[格雷编码][89]                                            |![rs]
@@ -1399,6 +1400,7 @@
 [81]:Problemset/0081-Search%20in%20Rotated%20Sorted%20Array%20II/README_CN.md#81-搜索旋转排序数组-ii
 [82]:Problemset/0082-Remove%20Duplicates%20from%20Sorted%20List%20II/README_CN.md#82-删除排序链表中的重复元素-ii
 [83]:Problemset/0083-Remove%20Duplicates%20from%20Sorted%20List/README_CN.md#83-删除排序链表中的重复元素
+[85]:Problemset/0085-Maximal%20Rectangle/README_CN.md#85-最大矩形
 [86]:Problemset/0086-Partition%20List/README_CN.md#86-分隔链表
 [88]:Problemset/0088-Merge%20Sorted%20Array/README_CN.md#88-合并两个有序数组
 [89]:Problemset/0089-Gray%20Code/README_CN.md#89-格雷编码
@@ -2723,6 +2725,7 @@
 [81l]:https://leetcode.cn/problems/search-in-rotated-sorted-array-ii/
 [82l]:https://leetcode.cn/problems/remove-duplicates-from-sorted-list-ii/
 [83l]:https://leetcode.cn/problems/remove-duplicates-from-sorted-list/
+[85l]:https://leetcode.cn/problems/maximal-rectangle/
 [84l]:https://leetcode.cn/problems/largest-rectangle-in-histogram/
 [86l]:https://leetcode.cn/problems/partition-list/
 [88l]:https://leetcode.cn/problems/merge-sorted-array/