function diagonalDifference(arr) {
    const n = arr.length;
    let i = 0;
    let j = 0;
    let k = n - 1;
    let leftDiag = 0;
    let rightDiag = 0;

    while (i < n && j < n) {
        leftDiag += arr[i][j];
        rightDiag += arr[i][k];
        i++;
        j++;
        k--;
    }
    
    return Math.abs(leftDiag - rightDiag);
}