给定一个仅包含 0 和 1 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:
代码语言：javascript复制输入:
[
["1","0","1","0","0"],
["1","0","1","1","1"],
["1","1","1","1","1"],
["1","0","0","1","0"]
]
输出: 6解：和84题，同样使用单调栈，但是比上题难理解很多。
代码语言：javascript复制 public int maximalRectangle(char[][] matrix) {
int rLen = matrix.length;
int cLen = rLen == 0 ? 0 : matrix[0].length;
int max = 0;
int[] h = new int[cLen 1];
for (int row = 0; row < rLen; row ) {
//每行维护一个单调栈
Stack<Integer> s = new Stack<Integer>();
s.push(-1);
for (int i = 0; i <= cLen; i ) {
//遍历每一行的累计高度
if (i < cLen && matrix[row][i] == '1') {
h[i] = 1;
} else {
h[i] = 0;
}
//破坏单调栈
while (s.peek() != -1 && h[i] < h[s.peek()]) {
int yIdx = s.pop();
int y = h[yIdx];//矩形宽
int xIdx = s.peek();
int x = i - xIdx - 1;//矩形长
max = Math.max(max, x * y);
}
s.push(i);
}
}
return max;
}
