LeetCode Largest Rectangle in Histogram(単調スタック)

Given n non-negative integers representing the histogram's bar height where the width of each bar is 1, find the area of largest rectangle in the histogram.
Above is a histogram where width of each bar is 1, given height =  [2,1,5,6,2,3] .
The largest rectangle is shown in the shaded area, which has area =  10  unit.
For example, Given height =  [2,1,5,6,2,3] ,
return  10 .
ヒストグラムの中で最大面積の矩形を求めます.
構想:単調スタックの応用.単調に増加するスタックを維持して、ネット上で書いたのは回転することができます:問題解

public class Solution {
    public int largestRectangleArea(int[] height) {
        Stack stack = new Stack();
        int i = 0;
        int ans = 0;
        int h[] = new int[height.length+1];
        h = Arrays.copyOf(height, height.length+1);
        while (i < h.length) {
        	if (stack.isEmpty() || h[stack.peek()] <= h[i])
        		stack.push(i++);
        	else {
        		int t = stack.pop();
        		ans = Math.max(ans, h[t] * (stack.isEmpty() ? i : i - stack.peek() - 1));
        	}
        }
        
        return ans;
    }
}