freecodecamp--freecodecamp/curriculum/challenges/english/blocks/daily-coding-challenges-javascript/6a0dcd03ee4e68698080ef67.md

id, title, challengeType, dashedName

id	title	challengeType	dashedName
6a0dcd03ee4e68698080ef67	Challenge 303: Roommates	28	challenge-303

--description--

Given an array of people and their roommate group, return the room assignments for a hotel stay using the following rules:

• Each person has a name and a group property:

[
  { "name": "Alice", "group": "A" },
  { "name": "Bob", "group": "B" },
  { "name": "Carol", "group": "A" }
]

• People can only share a room with someone from the same group and are paired in the order they are given.
• Return an array of strings with names separated by " and " for a shared room, and just the name for a solo room. Names must appear in the order they were paired. For the example above, return ["Alice and Carol", "Bob"].

--hints--

getRoommates([{ "name": "Alice", "group": "A" }, { "name": "Bob", "group": "B" }, { "name": "Carol", "group": "A" }]) should return ["Alice and Carol", "Bob"].

assert.deepEqual(getRoommates([{ "name": "Alice", "group": "A" }, { "name": "Bob", "group": "B" }, { "name": "Carol", "group": "A" }]).sort(), ["Alice and Carol", "Bob"].sort());

getRoommates([{ "name": "John", "group": "C" }, { "name": "Julia", "group": "C" }, { "name": "Jim", "group": "C" }]) should return ["John and Julia", "Jim"].

assert.deepEqual(getRoommates([{ "name": "John", "group": "C" }, { "name": "Julia", "group": "C" }, { "name": "Jim", "group": "C" }]).sort(), ["John and Julia", "Jim"].sort());

getRoommates([{ "name": "Adam", "group": "D" }, { "name": "Abraham", "group": "E" }, { "name": "Austin", "group": "E" }, { "name": "Augustus", "group": "D" }, { "name": "Angelica", "group": "D" }, { "name": "Aaron", "group": "E" }]) should return ["Adam and Augustus", "Angelica", "Abraham and Austin", "Aaron"].

assert.deepEqual(getRoommates([{ "name": "Adam", "group": "D" }, { "name": "Abraham", "group": "E" }, { "name": "Austin", "group": "E" }, { "name": "Augustus", "group": "D" }, { "name": "Angelica", "group": "D" }, { "name": "Aaron", "group": "E" }]).sort(), ["Adam and Augustus", "Angelica", "Abraham and Austin", "Aaron"].sort());

getRoommates([{ "name": "Frank", "group": "A" }, { "name": "Emitt", "group": "B" }, { "name": "Daria", "group": "F" }, { "name": "Charles", "group": "D" }, { "name": "Bailey", "group": "A" }, { "name": "Albert", "group": "F" }]) should return ["Frank and Bailey", "Emitt", "Daria and Albert", "Charles"].

assert.deepEqual(getRoommates([{ "name": "Frank", "group": "A" }, { "name": "Emitt", "group": "B" }, { "name": "Daria", "group": "F" }, { "name": "Charles", "group": "D" }, { "name": "Bailey", "group": "A" }, { "name": "Albert", "group": "F" }]).sort(), ["Frank and Bailey", "Emitt", "Daria and Albert", "Charles"].sort());

getRoommates([{ "name": "Kevin", "group": "A" }, { "name": "Yuri", "group": "A" }, { "name": "Hugo", "group": "B" }, { "name": "Violet", "group": "A" }, { "name": "Brett", "group": "A" }, { "name": "Wayne", "group": "B" }]) should return ["Kevin and Yuri", "Violet and Brett", "Hugo and Wayne"].

assert.deepEqual(getRoommates([{ "name": "Kevin", "group": "A" }, { "name": "Yuri", "group": "A" }, { "name": "Hugo", "group": "B" }, { "name": "Violet", "group": "A" }, { "name": "Brett", "group": "A" }, { "name": "Wayne", "group": "B" }]).sort(), ["Kevin and Yuri", "Violet and Brett", "Hugo and Wayne"].sort());

--seed--

--seed-contents--

function getRoommates(people) {

  return people;
}

--solutions--

function getRoommates(people) {
  const groups = {};

  for (const { name, group } of people) {
    (groups[group] = groups[group] || []).push(name);
  }

  return Object.values(groups).flatMap(group => {
    const rooms = [];
    for (let i = 0; i < group.length; i += 2) {
      rooms.push(group.slice(i, i + 2).join(" and "));
    }
    return rooms;
  });
}