85 Time Limit Exceeded

Author: aQua

Algorithms/0085.maximal-rectangle/README.md

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+# [85. Maximal Rectangle](https://leetcode.com/problems/maximal-rectangle/)
+
+## 题目
+Given a 2D binary matrix filled with 0's and 1's, find the largest rectangle containing only 1's and return its area.
+
+For example, given the following matrix:
+```
+1 0 1 0 0
+1 0 1 1 1
+1 1 1 1 1
+1 0 0 1 0
+```
+Return 6.
+
+## 解题思路
+
+见程序注释

Algorithms/0085.maximal-rectangle/maximal-rectangle.go

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+package Problem0085
+
+func maximalRectangle(mat [][]byte) int {
+	m := len(mat)
+	if m == 0 {
+		return 0
+	}
+	n := len(mat[0])
+	if n == 0 {
+		return 0
+	}
+
+	check := func(ax, ay, bx, by int) int {
+		for i := ax; i <= bx; i++ {
+			for j := ay; j <= by; j++ {
+				if mat[i][j] == '0' {
+					return 0
+				}
+			}
+		}
+		return (bx - ax + 1) * (by - ay + 1)
+	}
+
+	max := 0
+	for ax := 0; ax < m; ax++ {
+		for ay := 0; ay < n; ay++ {
+			for bx := ax; bx < m; bx++ {
+				for by := ay; by < n; by++ {
+					tmp := check(ax, ay, bx, by)
+					if max < tmp {
+						max = tmp
+					}
+				}
+			}
+		}
+	}
+	
+	return max
+}