Python solution:

def diagonalDifference(arr): sum1 = 0 sum2 = 0 for i in range(0,n): sum1 += arr[i][i] sum2 += arr[i][n-i-1] return abs(sum1 - sum2)

Rate my solution:

function diagonalDifference(arr: number[][]): number {
    let firstDiagonal = 0;
    let secondDiagonal = 0;

    for(let i = 0; i < arr.length; i++) {
        for (let j = 0; j < arr[i].length; j++) {
            if (i === j) firstDiagonal += arr[i][j]; // sum of a11, a22, a33, ...
            if (j === arr.length - i - 1) secondDiagonal += arr[i][j] // sum of a1n, a2(n-1), a3(n-2), ...
        }
    }

    return Math.abs(firstDiagonal - secondDiagonal);
}

let suma01 = 0;

let suma02 = 0;

let n = arr.length;

for(let i = 0; i < arr.length; i++) { for(let j = 0; j < arr.length; j++) {

    if(i === j ) {

        suma01 = suma01 +  arr[i][j]


    } 



    if (i +j === n - 1)  {

         suma02 =  suma02 + arr[i][j]

    }

}

HI this is my solution, what's wrong in this!

function diagonalDifference(arr) {
    let d1 = 0;
    let d2 = 0;
   
   for(let i=0;i<arr.length;i++) {
     d1 +=arr[i][i];
     d2 +=arr[i][arr.length - 1 - i];
   }
  return d2 - d1;
}

def diagonalDifference(arr): # Write your code here first_diagonal = 0 second_diagonal = 0

i = 0
for j in range(len(arr[i])):
    first_diagonal += arr[i][j]
    i += 1

i = 0
for j in range(len((arr[i]))):
    second_diagonal += arr[i][::-1][j]
    i += 1
result = first_diagonal - second_diagonal
return abs(result)