Trapping Rain Water

Trapping Rain Water

问题：

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.

思路:

　　数组的特别，拿到最高点的值，左右两边再分别测试

我的代码：

public class Solution {

    public int trap(int[] A) {

        if(A == null || A.length == 0) return 0;

        int maxIndex = -1;

        int maxValue = Integer.MIN_VALUE;

        for(int i = 0; i < A.length; i++)

        {

            if(maxValue < A[i])

            {

                maxIndex = i;

                maxValue = A[i];

            }

        }

        int maxRes = 0;

        int curMax = A[0];

        for(int i = 1; i <= maxIndex; i++)

        {

            if(A[i] < curMax)

            {

                maxRes += curMax - A[i];

            }

            else

            {

                curMax = A[i];

            }

        }

        

        curMax = A[A.length - 1];

        for(int i = A.length - 1; i >= maxIndex; i--)

        {

            if(A[i] < curMax)

            {

                maxRes += curMax - A[i];

            }

            else

            {

                curMax = A[i];

            }

        }

        return maxRes;

    }

}

View Code

学习之处：

　　抓住数组最高点的特征