HackerRank Day 11 2D arrays 30 days of code solution

YASH PAL,

HackerRank Day 11 2D Arrays solution – In this HackerRank Day 11 2D arrays 30 days of code problem, we need to develop a program that can take a 2d array as an input and then print the maximum hourglass sum of that array.

Objective
Today, we are building on our knowledge of arrays by adding another dimension.

Context
Given a 6 x 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 6 hourglasses in A, and an hourglass sum is the sum of an hourglass’ values.

Task
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.

Problem solution in Python 2 programming.      

#!/bin/python

import sys

def countHourglass(arr, i, j):
    hg = 0
    hg += arr[i][j]
    hg += arr[i-1][j-1] + arr[i-1][j] + arr[i-1][j+1]
    hg += arr[i+1][j-1] + arr[i+1][j] + arr[i+1][j+1]
    return hg
   
def getMaxHourglass(arr):
    maxHg = -999999
    for i in range(1, 5):
        for j in range(1, 5):
            hg = countHourglass(arr, i, j)
            maxHg = hg if hg > maxHg else maxHg
    return maxHg
            

arr = []
for arr_i in xrange(6):
   arr_temp = map(int,raw_input().strip().split(' '))
   arr.append(arr_temp)
print getMaxHourglass(arr)

Problem solution in Python 3 programming.

#!/bin/python3

import math
import os
import random
import re
import sys

if __name__ == '__main__':
    arr = []

    for _ in range(6):
        arr.append(list(map(int, input().rstrip().split())))
    sum = 0
    tarr = []
    
    for l in range(0,4):
        for k in range(0,4):
            for i in range(l,l+3):
                for j in range(k,k+3):
                    if i == l+1 and ( j == k or j == k+2):
                        continue
                    else:
                        sum += arr[i][j]
            tarr.append(sum)
            sum = 0
    
    print(max(tarr))

Problem solution in java programming.

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) {
        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 maxval = -9*6;
        for(int i=0; i<4; i++) {
            for(int j=0; j<4; j++) {
                int sum = arr[i][j] + arr[i][j+1] + arr[i][j+2];
                sum += arr[i+1][j+1];
                sum += arr[i+2][j] + arr[i+2][j+1] + arr[i+2][j+2];
                if(sum>maxval) {
                    maxval = sum;
                }
            }
        }
        System.out.println(maxval);
    }
}

Problem solution in c++ programming.

#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
using namespace std;

int add(int arr[6][6], int arr_i, int arr_j){
    int sum = arr[arr_i][arr_j];
    sum += arr[arr_i][arr_j +1];
    sum += arr[arr_i][arr_j +2];
    sum += arr[arr_i +1][arr_j +1];
    sum += arr[arr_i +2][arr_j];
    sum += arr[arr_i +2][arr_j +1];
    sum += arr[arr_i +2][arr_j +2];
    return sum;
}

int main(){
    int sum = -9 * 7;
    int arr[6][6];
    for(int arr_i = 0;arr_i < 6;arr_i++){
       for(int arr_j = 0;arr_j < 6;arr_j++){
          cin >> arr[arr_i][arr_j];
       }
    }
    for(int arr_i  = 0;arr_i < 4;arr_i++){
        for(int arr_j  = 0;arr_j < 4;arr_j++){
            int t = add(arr, arr_i, arr_j);
            if(t > sum)
                sum = t;
        }
    }
    cout << sum << endl;
    return 0;
}

Problem solution in c programming.

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

int soln(int arr[6][6]) {
    int i, j, sum,temp_sum;
    temp_sum = 0;
    sum = -9999999;
    for(i=0; i<6-2;i++) {
        for(j=0; j<6-2;j++){
            temp_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];
            //printf("%d %d %dn", arr[i][j], arr[i][j+1], arr[i][j+2]);
            //printf("  %d   n", arr[i+1][j+1]);
            //printf("%d %d %dn", arr[i+2][j] ,arr[i+2][j+1] ,arr[i+2][j+2]);
            //printf("temp sum: %d nn", temp_sum);
            if(temp_sum > sum) {
                sum = temp_sum;
            }
        }
    }
    return sum;
}

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]);
       }
    }
    printf("%dn", soln(arr));
    return 0;
}

Problem solution in 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();    
});

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);
    }
    /* row i, column j
     * 1 1 1
     * 1 1 1
     * 1 1 1 
     */
    var arrs = []
    for (var i = 1; i < arr.length - 1;i++){
        for (var j = 1; j < arr[i].length - 1; j++){
            var sum = 0;
            // top
            sum = parseInt(arr[i-1][j-1]) + parseInt(arr[i-1][j]) + parseInt(arr[i-1][j+1]);
            // middle
            sum = sum + parseInt(arr[i][j]);
            // bottom
            sum = sum + parseInt(arr[i+1][j-1]) + parseInt(arr[i+1][j]) + parseInt(arr[i+1][j+1]);
            arrs.push(sum);
        }
    }
    //console.log(arrs);
    console.log(Math.max.apply(null, arrs));

}

30 days of code coding problems solutions