Trapping Rain Water

浏览数：37 / 时间：2015年06月11日

Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it is able to trap after raining.

For example,
Given [0,1,0,2,1,0,1,3,2,1,2,1], return 6.

The above elevation map is represented by array [0,1,0,2,1,0,1,3,2,1,2,1]. In this case, 6 units of rain water (blue section) are being trapped. Thanks Marcos for contributing this image!

答案

public class Solution {
    public int trap(int[] A) {
        if(A==null||A.length<=2)
        {
            return 0;
        }
        int N=A.length;
        int []left=new int[N];
        int result=0;
        left[0]=A[0];
        for(int index=1;index<N;index++)
        {
            left[index]=Math.max(left[index-1],A[index]);
        }
        for(int i=N-1;i>0;i--)
        {
            int height=Math.min(left[i-1],A[i]);
            for(int j=i-1;A[j]<height;j--)
            {
                result+=height-A[j];
                A[j]=height;
            }
        }
        return result;
    }
}

Array Stack Two Pointers

郑重声明：本站内容如果来自互联网及其他传播媒体，其版权均属原媒体及文章作者所有。转载目的在于传递更多信息及用于网络分享，并不代表本站赞同其观点和对其真实性负责，也不构成任何其他建议。

Trapping Rain Water