Solving Hackerrank's Diagonal Difference Problem Using JavaScript

To be more specific, we focus on writing a for loop with has more than one iterators.

[mohfitrahgiffari]

function diagonalDifference(arr) {
let diagonal1 = 0;
let diagonal2 = 0;

for (let i = 0 ; i<arr[0].length ; i++){
diagonal1 += arr[i][i]
diagonal2 += arr[i][arr.length - i - 1]
}

return Math.abs(diagonal1 - diagonal2)

}

just find another solution that might can help, i'm just sharing for people but thank you for your video, that really inspire me to find a solution

[TFlies]

Math.abs(sum) will take care of the absolute value?

[johnnathanbaxter]

I appreciate the help, you explained this concept very well. Keep up the videos!!

[sogggy]

just found your channel searching for hacker rank solution for this problem. great explanations to the problem. Please do more solutions for hacker rank and codewars. thanks

[eduardopreuss]

that's the answer I came up with, it worked

function trying(arr) {
let d1 = 0, d2 = 0;
for(let i = 0, j = arr[0].length-1; i < arr.length; i++, j--){
d1 += arr[i][i]
d2 += arr[j][i]
}
return Math.abs(d1-d2)
}

[robottopgaming]

very good work don't give up and continue to publicate videos of coding

[Kgorham]

Teaching pro tip - don't start by saying "it's easy" because the people looking at your video obviously didn't find it easy, and that can be discouraging.

[Andrew-K]

How do you look at the matrix and know the position of first_diagonal_sum 'arr[i][i]' and second_diagonal_sum 'arr[i][j]' ?

[iccon]

what if i want to add the numbers instead of subtracting

[Bigfaceee]

so these are 3 seperate arrays rather than just one?

[Gill_]

Hey, I tried this solution but it's not working, my test cases are failed can you please tell me what's the reason behind it as there's not any error just simply returning 0

[focus_hustle-ol]

why arr[0].length works?
if the arr = [9, 2, 8, 4, 3, 6, 7]
that means that you are trying to find the length of the "9"

[s.akhtarjoomun]

I'm a beginner. It took me time, but I was able to solve it on my own. Then I came here to see if there were other simpler methods. Mine turned out to be a little shorter. U may check it out:

function diagonalDifference(arr) {
let x = 0; let y = 0;
for (let i = arr.length - 1; i >= 0; i--) {
let j = arr.length - i - 1;
x = x + arr[j][j];
y = y + arr[i][j];
}
return Math.abs(x - y)
}

[mugiirakimathi]

I'm more confused now. What the hell did I get myself into?

[lvchiju]

Great solution, but I resolve by using “return Math.abs(first - second)”

[mugiirakimathi]

I'm more confused now. What the hell did I get myself into?