HackerRank 2D Array – DS Problem Solution

Yashwant Parihar,

This post will solve the 2D Array – DS Solution in HackerRank. Given a 6 x 6 2D array, arr. an hourglass is a subset of values with indices falling in the following pattern:

a b c  
  d  
e f g

There are 16 hourglasses in a 6 x 6 array. The hourglass sum is the sum of the values in an hourglass. Calculate the hourglass sum for every hourglass in arr, then print the maximum hourglass sum.
Example
arr =

-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

The 16 hourglass sums are:
-63, -34, -9, 12, 
-10,   0, 28, 23, 
-27, -11, -2, 10, 
  9,  17, 25, 18

The highest hourglass sum is 28 from the hourglass beginning at row 1, column 2:
0 4 3
  1
8 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 hourglass Sum with the following parameter(s):
int arr[6][6]: a 2-D array of integers


Returns
int: the maximum hourglass sum

Input Format
Each of the 6 lines of inputs arr[i] contains 6 space-separated integers arr[i][j].

Constraints
-9≤ arr[i][j] <9
0≤ j ≤5

Sample Input
1 1 1 0 0 0
0 1 0 0 0 0
1 1 1 0 0 0
0 0 2 4 4 0
0 0 0 2 0 0
0 0 1 2 4 0

Sample Output
19

HackerRank 2D Array – DS Solution in C

#include <math.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <limits.h>
#include <stdbool.h>

int main(){
    int arr[6][6];
    for(int arr_i = 0; arr_i < 6; arr_i++){
       for(int arr_j = 0; arr_j < 6; arr_j++){
          
          scanf("%d",&arr[arr_i][arr_j]);
       }
    }
    
    int maxNumber = 0;
    int temp = 0;
    for (int i = 0; i < 6; i++) {
        for (int j = 0; j < 6; j++) {
            if (i < 4 && j < 4) {
                temp = arr[i][j] + arr[i][j + 1] + arr[i][j + 2] + arr[i + 1][j + 1] + arr[i + 2][j] + arr[i + 2][j + 1] + arr[i + 2][j + 2];
                if (i == 0 && j == 0) {
                    maxNumber = temp;
                }
            }
            
            if (temp > maxNumber) {
                maxNumber = temp;
            }
                
        }
    }
    
    printf("%d",maxNumber);
    
    return 0;
}

HackerRank 2D Array – DS Solution in C++

#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    int arr[6][6],i,j,k,l,x,sum,max;
	for(i=0;i<6;i++)
		for(j=0;j<6;j++)
			cin>>arr[i][j];
	k=0;
	l=0;
	x=0;
	sum=0;
	max=-30;
	while(x<16){
		for(i=l;i<3+l;i=i+2){
			for(j=k;j<3+k;j++){
				sum+=arr[i][j];
			}
		}
		sum+=arr[i-3][j-2];
		if(sum>max){
			max=sum;
		}
		sum=0;
		x++;
		l=x/4;
		k=x%4;
	}
	cout<<max;
    return 0;
}

HackerRank 2D Array – DS Solution in Java

import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {
    
    public static void main(String[] args) {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
        
        Scanner scanner = new Scanner(System.in); 
        int[][] in = new int[6][6];
        for (int i = 0; i < 6; i++) {
            for(int j = 0; j < 6; j++) {
                in[i][j] = scanner.nextInt();
            }
        }
        
        
        int max = Integer.MIN_VALUE;
        
        for (int r = 0; r < 4; r++) {
            for(int c = 0; c < 4; c++) {
                int s = in[r][c] + in[r][c + 1] + in[r][c + 2] + in[r + 1][c + 1] + in[r + 2][c] + in[r + 2][c + 1] + in[r + 2][c + 2];
                if (s > max) {
                    max = s; 
                }
            }
        }
        
        System.out.println(max);        
    }
}

HackerRank 2D Array – DS Solution in JavaScript

process.stdin.resume();
process.stdin.setEncoding('ascii');

var input_stdin = "";
var input_stdin_array = "";
var input_currentline = 0;

process.stdin.on('data', function (data) {
    input_stdin += data;
});

process.stdin.on('end', function () {
    input_stdin_array = input_stdin.split("\n");
    main();    
});

function readLine() {
    return input_stdin_array[input_currentline++];
}

/////////////// ignore above this line ////////////////////

function main() {
    var arr = [];
    for(arr_i = 0; arr_i < 6; arr_i++){
       arr[arr_i] = readLine().split(' ');
       arr[arr_i] = arr[arr_i].map(Number);
    }
    var max=-9999;
    for(i=0;i<4;i++){
        for(j=0;j<4;j++){
              var temp=arr[i][j]+arr[i][j+1]+arr[i][j+2]+arr[i+1][j+1]+arr[i+2][j]+arr[i+2][j+1]+arr[i+2][j+2];   
            if(temp>max)
                max=temp
        }
    }
    console.log(max);
}

HackerRank 2D Array – DS Solution in Python

#!/bin/python

import sys


arr = []
for arr_i in xrange(6):
    arr_temp = map(int, raw_input().strip().split(' '))
    arr.append(arr_temp)
    
def hourglass_sum(matrix, row, column):
    return matrix[row][column - 1] + matrix[row][column] + matrix[row][column + 1] + \
           matrix[row + 1][column] + \
           matrix[row + 2][column - 1] + matrix[row + 2][column] + matrix[row + 2][column + 1]
    
hourglass_sums = [hourglass_sum(arr, row, column) for row in xrange(4) for column in xrange(1, 5)]
    
print max(hourglass_sums)

Other Solutions:

HackerRank Dynamic Array Problem Solution

HackerRank Solutions