fair-rations.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', _ => {
    inputString = inputString.replace(/\s*$/, '')
        .split('\n')
        .map(str => str.replace(/\s*$/, ''));

    main();
});

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

// Complete the fairRations function below.
function fairRations(B) {
    let count = 0;
    let i = 0;
    while (i < B.length) {
        if (B[i] % 2 !== 0 && (i + 1) < B.length) {
            B[i] = B[i] + 1;
            B[i + 1] = B[i + 1] + 1;
            count += 2;
        }
        i++;
    }
    i = 0;
    while (i < B.length) {
        if (B[i] % 2 !== 0){
           return "NO";
        }
        i++;
    }
    return count;
}

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

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

    const B = readLine().split(' ').map(BTemp => parseInt(BTemp, 10));

    let result = fairRations(B);

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

    ws.end();
}