Java for LeetCode 084 Largest Rectangle in Histogram【HARD】

[2,1,5,6,2,3]

10

public int largestRectangleArea(int[] height) {
Stack<Integer> stk = new Stack<Integer>();
int ret = 0;
for (int i = 0; i <= height.length; i++) {
int h=0;
if(i<height.length)
h=height[i];
if (stk.isEmpty() || h >= height[stk.peek()])
stk.push(i);
else {
int top = stk.pop();
ret = Math.max(ret, height[top] * (stk.empty() ? i : i - stk.peek() - 1));
i--;
}
}
return ret;
}