关键:
记录左侧比当前值小的数据
每次加入数据时,将递增栈中的数据弹出
栈中保存数据的索引
public static int largestRectangleArea(int[] arr){
if (arr == null || arr.length == 0){
return 0;
}
Stack<Integer> stack = new Stack();
int max = 0;
for (int i = 0; i <= arr.length; i++) {
int cur;
if (i == arr.length){
cur = 0;
}else {
cur = arr[i];
}
while (!stack.isEmpty() && cur <= arr[stack.peek()]){
int h = arr[stack.pop()];
int w = i;
if (!stack.isEmpty()){
w = i - stack.peek() - 1;
}
max = Math.max(max ,h*w);
}
stack.push(i);
}
return max;
}