[Leetcode] Largest Rectangle in Histogram

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.

 

Solution:

http://www.cnblogs.com/lichen782/p/leetcode_Largest_Rectangle_in_Histogram.html

这个大哥讲得太清楚了！！120个赞啊！！！

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