Method trap

TrappingRainWater.java:2–23

(int[] height)

class Solution {
    public int trap(int[] height) {
        int result=0;
        int i = 0, j = height.length - 1;
        int left_max = 0, right_max = 0;
        
        while(i<=j)
        {
            if(height[i]<height[j])
            {
                if(height[i]>left_max) left_max=height[i];
                else result+=left_max-height[i];
                i++;
            }
            else
            {
                if(height[j]>right_max) right_max=height[j];
                else result+=right_max-height[j];
                j--;
            }
        }
        return result;
    }
}