modify code

src/class25/Code03_LargestRectangleInHistogram.java

@@ -3,7 +3,7 @@ package class25;
 import java.util.Stack;
 
 // 测试链接：https://leetcode.com/problems/largest-rectangle-in-histogram
-public class Code04_LargestRectangleInHistogram {
+public class Code03_LargestRectangleInHistogram {
 
 	public static int largestRectangleArea1(int[] height) {
 		if (height == null || height.length == 0) {

src/class25/Code04_MaximalRectangle.java

@@ -0,0 +1,48 @@
+package class25;
+
+import java.util.Stack;
+
+// 测试链接：https://leetcode.com/problems/maximal-rectangle/
+public class Code04_MaximalRectangle {
+
+	public static int maximalRectangle(char[][] map) {
+		if (map == null || map.length == 0 || map[0].length == 0) {
+			return 0;
+		}
+		int maxArea = 0;
+		int[] height = new int[map[0].length];
+		for (int i = 0; i < map.length; i++) {
+			for (int j = 0; j < map[0].length; j++) {
+				height[j] = map[i][j] == '0' ? 0 : height[j] + 1;
+			}
+			maxArea = Math.max(maxRecFromBottom(height), maxArea);
+		}
+		return maxArea;
+	}
+
+	// height是正方图数组
+	public static int maxRecFromBottom(int[] height) {
+		if (height == null || height.length == 0) {
+			return 0;
+		}
+		int maxArea = 0;
+		Stack<Integer> stack = new Stack<Integer>();
+		for (int i = 0; i < height.length; i++) {
+			while (!stack.isEmpty() && height[i] <= height[stack.peek()]) {
+				int j = stack.pop();
+				int k = stack.isEmpty() ? -1 : stack.peek();
+				int curArea = (i - k - 1) * height[j];
+				maxArea = Math.max(maxArea, curArea);
+			}
+			stack.push(i);
+		}
+		while (!stack.isEmpty()) {
+			int j = stack.pop();
+			int k = stack.isEmpty() ? -1 : stack.peek();
+			int curArea = (height.length - k - 1) * height[j];
+			maxArea = Math.max(maxArea, curArea);
+		}
+		return maxArea;
+	}
+
+}

src/class25/Code05_CountSubmatricesWithAllOnes.java

@@ -0,0 +1,56 @@
+package class25;
+
+import java.util.Stack;
+
+// 测试链接：https://leetcode.com/problems/count-submatrices-with-all-ones
+public class Code05_CountSubmatricesWithAllOnes {
+
+	public static int numSubmat(int[][] mat) {
+		if (mat == null || mat.length == 0 || mat[0].length == 0) {
+			return 0;
+		}
+		int nums = 0;
+		int[] height = new int[mat[0].length];
+		for (int i = 0; i < mat.length; i++) {
+			for (int j = 0; j < mat[0].length; j++) {
+				height[j] = mat[i][j] == 0 ? 0 : height[j] + 1;
+			}
+			nums += countFromBottom(height);
+		}
+		return nums;
+
+	}
+
+	public static int countFromBottom(int[] height) {
+		if (height == null || height.length == 0) {
+			return 0;
+		}
+		int nums = 0;
+		Stack<Integer> stack = new Stack<Integer>();
+		for (int i = 0; i < height.length; i++) {
+			while (!stack.isEmpty() && height[stack.peek()] >= height[i]) {
+				int cur = stack.pop();
+				if (height[cur] > height[i]) {
+					int left = stack.isEmpty() ? -1 : stack.peek();
+					int n = i - left - 1;
+					int down = Math.max(left == -1 ? 0 : height[left], height[i]);
+					nums += (height[cur] - down) * num(n);
+				}
+			}
+			stack.push(i);
+		}
+		while (!stack.isEmpty()) {
+			int cur = stack.pop();
+			int left = stack.isEmpty() ? -1 : stack.peek();
+			int n = height.length - left - 1;
+			int down = left == -1 ? 0 : height[left];
+			nums += (height[cur] - down) * num(n);
+		}
+		return nums;
+	}
+
+	public static int num(int n) {
+		return ((n * (1 + n)) >> 1);
+	}
+
+}

src/class25/Code06_SumOfSubarrayMinimums.java

@@ -7,7 +7,7 @@ import java.util.Stack;
 // subArrayMinSum2是最优解的思路
 // sumSubarrayMins是最优解思路下的单调栈优化
 // Leetcode上只提交sumSubarrayMins方法，时间复杂度O(N)，可以直接通过
-public class Code03_SumOfSubarrayMinimums {
+public class Code06_SumOfSubarrayMinimums {
 
 	public static int subArrayMinSum1(int[] arr) {
 		int ans = 0;