Trapping Rainwater Java Code

Trapping Rainwater 

Trapping Rainwater Java Programming Code:

import java.util.*;

public class TrappingRainWater {

    public static int TrappingRain(int height[]) {

        int n = height.length;

        // claculate left max boundary - array

        int leftMax[] = new int[n];

        leftMax[0] = height[0];

        for (int i = 1; i < n; i++) {

            leftMax[i] = Math.max(height[i], leftMax[i - 1]);

        }

        // claculate right max boundary - array

        int rightMax[] = new int[n];

        rightMax[n - 1] = height[n - 1];

        for (int i = n - 2; i >= 0; i--) {

            rightMax[i] = Math.max(height[i], rightMax[i + 1]);

        }

        int trappedWater = 0;

        // loop

        for (int i = 0; i < n; i++) {

            // waterLevel = min(leftmax bound, right bound)

            int waterLevel = Math.min(leftMax[i], rightMax[i]);

            // trapped water = waterLevel - hight[i]

            trappedWater += waterLevel - height[i];

        }

        return trappedWater;

    }

    public static void main(String[] args) {

        int height[] = { 1, 4, 2, 0, 6, 3, 2, 5 };

        System.out.println(TrappingRain(height));

    }

}