Package Problem from CodeEval

Question.md

Package Problem

You want to send your friend a package with different things. Each thing you put inside the package has such parameters as index number, weight and cost. The package has a weight limit. Your goal is to determine which things to put into the package so that the total weight is less than or equal to the package limit and the total cost is as large as possible.

You would prefer to send a package which weights less in case there is more than one package with the same price.

https://www.codeeval.com/open_challenges/114/

Solution.js

const fs = require('fs');

function decreasingProductCostWithLowerWeight(productA, productB) {
  if (productA.cost === productB.cost) {
    return productA.weight - productB.weight;
  }

  return productB.cost - productA.cost;
}

function weightLessThan(weight) {
  return product => product.weight < weight;
}

function parseProductString(productStr) {
  const productArr = productStr.match(/\d+(\.\d+)?/g).map(Number);
  const index = productArr[0];
  const weight = productArr[1];
  const cost = productArr[2];

  return {
    cost,
    weight,
    index,
  };
}

fs
  .readFileSync(process.argv[2], 'utf-8')
  .trim()
  .split('\n')
  .map((line) => {
    // max weight that can be carried in a box
    const lineSplits = line.split(':');

    const MAX_WEIGHT = Number(lineSplits[0]);
    // console.log('Maximum Weight:', MAX_WEIGHT);

    const productsString = lineSplits[1].trim().split(' ');

    // console.log('Products String:', productsString);

    const products = productsString.map(parseProductString);
    // console.log('Products:', products);

    const validProducts = products.filter(weightLessThan(MAX_WEIGHT));
    // console.log('Valid Products: ', validProducts);

    return {
      maxWeight: MAX_WEIGHT,
      products: validProducts,
    };
  })
  .forEach(({ maxWeight, products }) => {
    // do something with each package
    if (products.length === 0) {
      console.log('-');
    }

    // sort products by cost (high to low)
    const productsByCost = products.sort(decreasingProductCostWithLowerWeight);

    const { indexes } = productsByCost.reduce(
      (acc, product) => {
        // eslint-disable-next-line prefer-destructuring, no-shadow
        const indexes = acc.indexes;
        // eslint-disable-next-line prefer-destructuring
        const totalWeight = acc.totalWeight;

        const predictedWeight = product.weight + totalWeight;
        if (predictedWeight <= maxWeight) {
          indexes.push(product.index);

          return {
            ...acc,
            indexes,
            totalWeight: predictedWeight,
          };
        }

        return acc;
      },
      {
        indexes: [],
        totalWeight: 0,
      },
    );

    // at the end, log the indexes
    const productIndexesStr = indexes.join(',');
    console.log(productIndexesStr);
  });