2D Array - DS HackerRank Solution

2D Array - DS HackerRank Solution
Source : https://www.hackerrank.com/challenges/2d-array

Given a 2D Array, :

1 1 1 0 0 00 1 0 0 0 01 1 1 0 0 00 0 0 0 0 00 0 0 0 0 00 0 0 0 0 0

We define an hourglass in to be a subset of values with indices falling in this pattern in 's graphical representation:

a b c  de f g

There are hourglasses in , and an hourglass sum is the sum of an hourglass' values. Calculate the hourglass sum for every hourglass in , then print the maximum hourglass sum.

For example, given the 2D array:

-9 -9 -9  1 1 1  0 -9  0  4 3 2-9 -9 -9  1 2 3 0  0  8  6 6 0 0  0  0 -2 0 0 0  0  1  2 4 0

We calculate the following hourglass values:

-63, -34, -9, 12, -10, 0, 28, 23, -27, -11, -2, 10, 9, 17, 25, 18

Our highest hourglass value is from the hourglass:

0 4 3  18 6 6

Note: If you have already solved the Java domain's Java 2D Array challenge, you may wish to skip this challenge.

Function Description

Complete the function hourglassSum in the editor below. It should return an integer, the maximum hourglass sum in the array.

hourglassSum has the following parameter(s):

• arr: an array of integers

Input Format

Each of the lines of inputs contains space-separated integers .

Constraints

Output Format

Print the largest (maximum) hourglass sum found in .

Sample Input

1 1 1 0 0 00 1 0 0 0 01 1 1 0 0 00 0 2 4 4 00 0 0 2 0 00 0 1 2 4 0

Sample Output

19

Explanation

contains the following hourglasses:

The hourglass with the maximum sum () is:

2 4 4  21 2 4

Source : https://www.hackerrank.com/challenges/2d-array

Solution

	// Karthikalapati.blogspot.com
	import java.util.Scanner;
	public class Solution {
	public static void main(String[] args) {
	Scanner scan = new Scanner(System.in);
	int arr[][] = new int[6][6];
	for (int row = 0; row < 6; row++) {
	for (int col = 0; col < 6; col++) {
	arr[row][col] = scan.nextInt();
	}
	}
	scan.close();
	System.out.println(maxHourglass(arr));
	}
	public static int maxHourglass(int [][] arr) {
	int max = Integer.MIN_VALUE;
	for (int row = 0; row < 4; row++) {
	for (int col = 0; col < 4; col++) {
	int sum = findSum(arr, row, col);
	max = Math.max(max, sum);
	}
	}
	return max;
	}
	private static int findSum(int [][] arr, int r, int c) {
	int sum = arr[r+0][c+0] + arr[r+0][c+1] + arr[r+0][c+2]
	+ arr[r+1][c+1] +
	arr[r+2][c+0] + arr[r+2][c+1] + arr[r+2][c+2];
	return sum;
	}
	}