Day 11: 2D Arrays HackerRank Solution

Day 11: 2D Arrays HackerRank Solution
Source : https://www.hackerrank.com/challenges/30-2d-arrays

Objective
Today, we're building on our knowledge of Arrays by adding another dimension. Check out the Tutorial tab for learning materials and an instructional video!

Context
Given a 2D Array, :

1 1 1 0 0 0
0 1 0 0 0 0
1 1 1 0 0 0
0 0 0 0 0 0
0 0 0 0 0 0
0 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.

Task
Calculate the hourglass sum for every hourglass in , then print the maximum hourglass sum.

Input Format

There are lines of input, where each line contains space-separated integers describing 2D Array ; every value in will be in the inclusive range of to .

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:

1 1 1   1 1 0   1 0 0   0 0 0  1       0       0       01 1 1   1 1 0   1 0 0   0 0 00 1 0   1 0 0   0 0 0   0 0 0  1       1       0       00 0 2   0 2 4   2 4 4   4 4 01 1 1   1 1 0   1 0 0   0 0 0  0       2       4       40 0 0   0 0 2   0 2 0   2 0 00 0 2   0 2 4   2 4 4   4 4 0  0       0       2       00 0 1   0 1 2   1 2 4   2 4 0

The hourglass with the maximum sum () is:

2 4 4  21 2 4

Source : https://www.hackerrank.com/challenges/30-2d-arrays

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;
	}
	}