Trailer Allocation

coding-challenge.js

const assert = require('assert').strict

const allocateTrailers = (carLengths, trailerLength) => {
    let remainder = trailerLength;
    const trailers = [];
    let used = 0

    while (used < carLengths.length) {
        remainder = trailerLength;
        const trailer = [];
        for (let i = 0; i < carLengths.length; i++) {
            if (carLengths[i] != null && carLengths[i] <= remainder) {
                trailer.push(i); // push index of the car into the trailer journal to identify the car
                remainder = remainder - carLengths[i];
                carLengths[i] = null;
                used++;
                if (remainder <= 0) break;
            } else if (carLengths[i] > trailerLength) {
                carLengths[i] = null;
                used++;
            }
        }
        trailers.push(trailer);
    }

    return trailers;
}

// Tests
assert.deepEqual(allocateTrailers([5, 5], 10), [[0,1]]);
assert.deepEqual(allocateTrailers([5, 5, 5, 3, 90], 10), [[0,1], [2,3]]);
console.log(allocateTrailers(Array(100).fill(5), 15));