function diagonalDifference(arr: number[][]): number {
    let ltrDiagonalSum = 0;
    let rtlDiagonalSum = 0;
    const length = arr.length;
    
    for (let i = 0; i < length; i++) {
        ltrDiagonalSum += arr[i][i];
        rtlDiagonalSum += arr[i][length - 1 - i];
    }
    
    return Math.abs(ltrDiagonalSum - rtlDiagonalSum);
}