## Algorithm

Problem Name: 30 days of code - Day 11: 2D Arrays

In this HackerRank in 30 Days of Code ay 11: 2D Arrays problem solution,

Objective
Today, we are 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 6 * 6 2D Array, A:

``````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 A to be a subset of values with indices falling in this pattern in A's graphical representation:

``````a b c
d
e f g
``````

There are 16 hourglasses in A, and an hourglass sum is the sum of an hourglass' values.

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

Example

In the array shown above, the maximum hourglass sum is 7 for the hourglass in the top left corner.

Input Format

There are 6 lines of input, where each line contains 6 space-separated integers that describe the 2D Array A.

Constraints

• -9 <= A[i][j] <= 9
• 0 <= i,j <= 5

Output Format

Print the maximum hourglass sum in A.

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
``````

Explanation

A contains the following hourglasses:

``````1 1 1   1 1 0   1 0 0   0 0 0
1       0       0       0
1 1 1   1 1 0   1 0 0   0 0 0

0 1 0   1 0 0   0 0 0   0 0 0
1       1       0       0
0 0 2   0 2 4   2 4 4   4 4 0

1 1 1   1 1 0   1 0 0   0 0 0
0       2       4       4
0 0 0   0 0 2   0 2 0   2 0 0

0 0 2   0 2 4   2 4 4   4 4 0
0       0       2       0
0 0 1   0 1 2   1 2 4   2 4 0
``````
The hourglass with the maximum sum (19) is:
``````2 4 4
2
1 2 4
``````

## Code Examples

### #1 Code Example with C Programming

```Code - C Programming```

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

int main(){
int arr[6][6];
for(int i = 0; i  <  6; i++){
for(int j = 0; j  <  6; j++){
scanf("%d", &arr[i][j]);
}
}
int max_sum = 0;
int temp_sum;
for(int i = 0; i  <  4; i++) {
for(int j = 0; j  <  4; j++) {
temp_sum = 0;
// top row
temp_sum += arr[i][j];
temp_sum += arr[i][j + 1];
temp_sum += arr[i][j + 2];
//middle
temp_sum += arr[i+1][j+1];
//bottom row
temp_sum += arr[i + 2][j];
temp_sum += arr[i + 2][j + 1];
temp_sum += arr[i + 2][j + 2];

//if first hourglass, set as max
if(temp_sum > max_sum || i == 0 && j == 0)
max_sum = temp_sum;
}
}
printf("%d\n", max_sum);
return 0;
}
``````
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### #2 Code Example with C++ Programming

```Code - C++ Programming```

``````
#include <iostream>
#include <vector>

using namespace std;

int main() {
vector < vector<int>> arr(6, vector<int>(6));
for (int i = 0; i  <  6; i++) {
for (int j = 0; j  <  6; j++) {
cin >> arr[i][j];
}
}

int max = -9 * 7;
for (int i = 0; i  <  6; i++) {
for (int j = 0; j  <  6; j++) {
if (j + 2 < 6 && i + 2 < 6) {
int sum = 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 (sum > max) max = sum;
}
}
}

cout << max;

return 0;
}
``````
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### #3 Code Example with C# Programming

```Code - C# Programming```

``````
using System;

class Solution
{
static void Main(String[] args)
{
int[][] arr = new int[6][];
for (int i = 0; i  <  6; i++)
{
arr[i] = Array.ConvertAll(tmp, int.Parse);
}

int max = -9 * 7;
for (int i = 0; i  <  6; i++)
{
for (int j = 0; j  <  6; j++)
{
if (j + 2 < 6 && i + 2 < 6)
{
int sum = 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 (sum > max) max = sum;
}
}
}

Console.WriteLine(max);
}
}
``````
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### #4 Code Example with Golang Programming

```Code - Golang Programming```

``````
package main

import "fmt"

func main() {
var a [6][6]int
var max int
for i := range a {
for j := range a[i] {
fmt.Scan(&a[i][j])
}
}

for i := 0; i  <  4; i++ {
for j := 0; j  <  4; j++ {
sumHourGlass := a[i][j] + a[i][j + 1] + a[i][j + 2] + a[i + 1][j + 1] + a[i + 2][j] + a[i + 2][j +1] + a[i + 2][j + 2]
if (i == 0 && j == 0) || sumHourGlass > max {
max = sumHourGlass
}
}
}
fmt.Println(max)
}
``````
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### #5 Code Example with Java Programming

```Code - Java Programming```

``````
import java.util.Scanner;

public class Solution {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
int arr[][] = new int[6][6];
for (int i = 0; i  <  6; i++) {
for (int j = 0; j  <  6; j++) {
arr[i][j] = in.nextInt();
}
}

int max = -9 * 7;
for (int i = 0; i  <  6; i++) {
for (int j = 0; j  <  6; j++) {
if (j + 2 < 6 && i + 2 < 6) {
int sum = 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 (sum > max) max = sum;
}
}
}

System.out.println(max);
}
}
``````
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### #6 Code Example with Javascript Programming

```Code - Javascript Programming```

``````
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();
});

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] = arr[arr_i].map(Number);
}

var sumarr = [];

var h = 0;
for (var i = 0; i  <  4; i++) {
for (var j = 0; j  <  4; j++) {
sumarr[h] = 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];
h++;
}
}

sumarr.sort();

var max = -99999;
for (var x = 0; x  <  16; x++){
if (sumarr[x] > max)
max = sumarr[x];
}

console.log(max);
}
``````
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### #7 Code Example with Python Programming

```Code - Python Programming```

``````
arr = []

for _ in range(6):
tmp = [int(x) for x in str(input()).split(" ")]
arr.append(tmp)

maximum = -9 * 7

for i in range(6):
for j in range(6):
if j + 2 < 6 and i + 2 < 6:
result = 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 result > maximum:
maximum = result

print(maximum)
``````
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