HackerRank - Diagonal Difference (JS)

main.js

'use strict';

const fs = require('fs');

process.stdin.resume();
process.stdin.setEncoding('utf-8');

let inputString = '';
let currentLine = 0;

process.stdin.on('data', inputStdin => {
    inputString += inputStdin;
});

process.stdin.on('end', function() {
    inputString = inputString.replace(/\s*$/, '')
        .split('\n')
        .map(str => str.replace(/\s*$/, ''));

    main();
});

function readLine() {
    return inputString[currentLine++];
}

// Complete the diagonalDifference function below.
function diagonalDifference(arr) {
    const arrLength = arr.length;
    const maxIndex = arrLength-1;
    let leftDiagonalSum = 0;
    let rightDiagonalSum = 0;
    
    for(let i=0; i<arrLength;i++){
        leftDiagonalSum += arr[i][i];
        rightDiagonalSum += arr[i][maxIndex-i];
    }

    return Math.abs(leftDiagonalSum-rightDiagonalSum);
}

function main() {
    const ws = fs.createWriteStream(process.env.OUTPUT_PATH);

    const n = parseInt(readLine(), 10);

    let arr = Array(n);

    for (let i = 0; i < n; i++) {
        arr[i] = readLine().split(' ').map(arrTemp => parseInt(arrTemp, 10));
    }

    const result = diagonalDifference(arr,n);

    ws.write(result + '\n');

    ws.end();
}