2D Array - HackerRank JavaScript Solution

Given a 6 X 6 Array arr:

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

An hourglass in A is a subset of values with indices falling in this pattern in arr's graphical representation:

a b c
  d
e f g

There are 16 hourglasses in arr. An hourglass sum is the sum of an hourglass' values. Calculate the hourglass sum for every hourglass in arr, then print the maximum hourglass sum. The array will always be 6 X 6.

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

Function Description

Complete the function hourglassSum in the editor below.

hourglassSum has the following parameter(s):

• int arr[6][6]: an 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].

Solution

function hourglassSum(arr) {
    // Write your code here
    let maxSum = ''
    for (let step1 = 0; step1 < arr.length-2; step1++){
        for (let step2 = 0; step2 < arr.length-2; step2++){
            const currentSum = arr[step1][step2] + arr[step1][step2+1] 
         + arr[step1][step2+2] + arr[step1+1][step2+1] 
         + arr[step1+2][step2] + arr[step1+2][step2+1] 
         + arr[step1+2][step2+2]

            if(currentSum <= 0){
               const temp = currentSum
               if (typeof maxSum == 'string' ){
                   maxSum = temp
               } else if(temp == 0 && maxSum <= 0){
                   maxSum = temp
               }
                else if(temp > maxSum){
                   maxSum = temp
               }
            } else if(currentSum > maxSum){
                maxSum = currentSum
            } 
        }
    }
    return maxSum
}

Comments

[Frank Wisniewski]

let myArray = ['-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']
function hourGlassSum (arr, sum=0){
  let hourGlass= function(myArray, y,x, myHour=[], mySum=0){    
    myHour.push([y,x],[y,x+1],[y,x+2],[y+1,x+1],[y+2,x],[y+2,x+1],[y+2,x+2])
    myHour.forEach(function (el){
      (el[0] in myArray && el[1] in myArray[el[0]])?
      mySum+=+myArray[el[0]][el[1]]: mySum=0;})
    return mySum
  }  
  arr.forEach((el,i)=>arr[i]=(el.split(' ')));    
  arr.forEach((el,i) =>
    arr[i].forEach( (el,k) =>
      sum=sum+hourGlass(arr,i,k)))
  return sum;
}
console.log(hourGlassSum(myArray))