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Challenge 196: 2026 Winter Games Day 17: Closing Day

curriculum/challenges/english/blocks/daily-coding-challenges-javascript/697a49e9860d24853adef681.md

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--description--

Given a 2D array of medal winners, return a medal count for each country as a CSV string.

  • In the given array, each sub-array represents a single event: [gold_winner, silver_winner, bronze_winner]

  • The returned CSV string should have the following format, with the first line being headers:

sh
Country,Gold,Silver,Bronze,Total
country_name,gold_count,silver_count,bronze_count,total_medals
  • Separate new lines with the new line character ("\n").
  • Do not include spaces around commas or at the end of lines.
  • Sort the returned CSV by gold medal count, highest first. If two countries have the same gold medal count, sort the tied ones alphabetically.

For example, given:

js
[
  ["USA", "CAN", "NOR"],
  ["NOR", "USA", "CAN"],
  ["USA", "NOR", "SWE"]
]

Return:

sh
"Country,Gold,Silver,Bronze,Total\nUSA,2,1,0,3\nNOR,1,1,1,3\nCAN,0,1,1,2\nSWE,0,0,1,1"

Which looks like this when printed:

sh
Country,Gold,Silver,Bronze,Total
USA,2,1,0,3
NOR,1,1,1,3
CAN,0,1,1,2
SWE,0,0,1,1

--hints--

countMedals([["USA", "CAN", "NOR"], ["NOR", "USA", "CAN"], ["USA", "NOR", "SWE"]]) should return "Country,Gold,Silver,Bronze,Total\nUSA,2,1,0,3\nNOR,1,1,1,3\nCAN,0,1,1,2\nSWE,0,0,1,1".

js
assert.equal(countMedals([["USA", "CAN", "NOR"], ["NOR", "USA", "CAN"], ["USA", "NOR", "SWE"]]), "Country,Gold,Silver,Bronze,Total\nUSA,2,1,0,3\nNOR,1,1,1,3\nCAN,0,1,1,2\nSWE,0,0,1,1");

countMedals([["NOR","SWE","FIN"]]) should return "Country,Gold,Silver,Bronze,Total\nNOR,1,0,0,1\nFIN,0,0,1,1\nSWE,0,1,0,1".

js
assert.equal(countMedals([["NOR","SWE","FIN"]]), "Country,Gold,Silver,Bronze,Total\nNOR,1,0,0,1\nFIN,0,0,1,1\nSWE,0,1,0,1");

countMedals([["ITA", "CHN", "CHN"], ["JPN", "ITA", "JPN"]]) should return "Country,Gold,Silver,Bronze,Total\nITA,1,1,0,2\nJPN,1,0,1,2\nCHN,0,1,1,2".

js
assert.equal(countMedals([["ITA", "CHN", "CHN"], ["JPN", "ITA", "JPN"]]), "Country,Gold,Silver,Bronze,Total\nITA,1,1,0,2\nJPN,1,0,1,2\nCHN,0,1,1,2");

countMedals([["USA","CAN","NOR"], ["GER","FRA","ITA"], ["JPN","KOR","CHN"], ["SWE","FIN","NOR"], ["CAN","USA","SWE"], ["FRA","GER","ITA"]]) should return "Country,Gold,Silver,Bronze,Total\nCAN,1,1,0,2\nFRA,1,1,0,2\nGER,1,1,0,2\nJPN,1,0,0,1\nSWE,1,0,1,2\nUSA,1,1,0,2\nCHN,0,0,1,1\nFIN,0,1,0,1\nITA,0,0,2,2\nKOR,0,1,0,1\nNOR,0,0,2,2".

js
assert.equal(countMedals([["USA","CAN","NOR"], ["GER","FRA","ITA"], ["JPN","KOR","CHN"], ["SWE","FIN","NOR"], ["CAN","USA","SWE"], ["FRA","GER","ITA"]]), "Country,Gold,Silver,Bronze,Total\nCAN,1,1,0,2\nFRA,1,1,0,2\nGER,1,1,0,2\nJPN,1,0,0,1\nSWE,1,0,1,2\nUSA,1,1,0,2\nCHN,0,0,1,1\nFIN,0,1,0,1\nITA,0,0,2,2\nKOR,0,1,0,1\nNOR,0,0,2,2");

countMedals([["ESP","ITA","FRA"], ["ITA","ESP","GER"], ["NOR","SWE","FIN"], ["FIN","NOR","SWE"], ["USA","CAN","MEX"], ["CAN","USA","MEX"], ["JPN","KOR","CHN"], ["CHN","JPN","KOR"]]) should return "Country,Gold,Silver,Bronze,Total\nCAN,1,1,0,2\nCHN,1,0,1,2\nESP,1,1,0,2\nFIN,1,0,1,2\nITA,1,1,0,2\nJPN,1,1,0,2\nNOR,1,1,0,2\nUSA,1,1,0,2\nFRA,0,0,1,1\nGER,0,0,1,1\nKOR,0,1,1,2\nMEX,0,0,2,2\nSWE,0,1,1,2".

js
assert.equal(countMedals([["ESP","ITA","FRA"], ["ITA","ESP","GER"], ["NOR","SWE","FIN"], ["FIN","NOR","SWE"], ["USA","CAN","MEX"], ["CAN","USA","MEX"], ["JPN","KOR","CHN"], ["CHN","JPN","KOR"]]), "Country,Gold,Silver,Bronze,Total\nCAN,1,1,0,2\nCHN,1,0,1,2\nESP,1,1,0,2\nFIN,1,0,1,2\nITA,1,1,0,2\nJPN,1,1,0,2\nNOR,1,1,0,2\nUSA,1,1,0,2\nFRA,0,0,1,1\nGER,0,0,1,1\nKOR,0,1,1,2\nMEX,0,0,2,2\nSWE,0,1,1,2");

countMedals([["USA","CAN","GER"], ["NOR","SWE","FIN"], ["USA","NOR","SWE"], ["GER","FRA","ITA"], ["JPN","KOR","CHN"], ["USA","GER","CAN"], ["SWE","NOR","FIN"], ["CAN","USA","NOR"], ["FRA","GER","ITA"], ["JPN","CHN","KOR"], ["SWE","FIN","NOR"], ["GER","ITA","FRA"]]) should return "Country,Gold,Silver,Bronze,Total\nUSA,3,1,0,4\nGER,2,2,1,5\nJPN,2,0,0,2\nSWE,2,1,1,4\nCAN,1,1,1,3\nFRA,1,1,1,3\nNOR,1,2,2,5\nCHN,0,1,1,2\nFIN,0,1,2,3\nITA,0,1,2,3\nKOR,0,1,1,2".

js
assert.equal(countMedals([["USA","CAN","GER"], ["NOR","SWE","FIN"], ["USA","NOR","SWE"], ["GER","FRA","ITA"], ["JPN","KOR","CHN"], ["USA","GER","CAN"], ["SWE","NOR","FIN"], ["CAN","USA","NOR"], ["FRA","GER","ITA"], ["JPN","CHN","KOR"], ["SWE","FIN","NOR"], ["GER","ITA","FRA"]]), "Country,Gold,Silver,Bronze,Total\nUSA,3,1,0,4\nGER,2,2,1,5\nJPN,2,0,0,2\nSWE,2,1,1,4\nCAN,1,1,1,3\nFRA,1,1,1,3\nNOR,1,2,2,5\nCHN,0,1,1,2\nFIN,0,1,2,3\nITA,0,1,2,3\nKOR,0,1,1,2");

--seed--

--seed-contents--

js
function countMedals(winners) {

  return winners;
}

--solutions--

js
function countMedals(winners) {
  const counts = {};

  for (const [gold, silver, bronze] of winners) {
    if (!counts[gold]) counts[gold] = { Gold: 0, Silver: 0, Bronze: 0 };
    if (!counts[silver]) counts[silver] = { Gold: 0, Silver: 0, Bronze: 0 };
    if (!counts[bronze]) counts[bronze] = { Gold: 0, Silver: 0, Bronze: 0 };

    counts[gold].Gold += 1;
    counts[silver].Silver += 1;
    counts[bronze].Bronze += 1;
  }

  const countries = Object.entries(counts).map(([country, medals]) => ({
    Country: country,
    Gold: medals.Gold,
    Silver: medals.Silver,
    Bronze: medals.Bronze,
    Total: medals.Gold + medals.Silver + medals.Bronze
  }));

  countries.sort((a, b) => b.Gold - a.Gold || a.Country.localeCompare(b.Country));

  const lines = ["Country,Gold,Silver,Bronze,Total"];
  for (const c of countries) {
    lines.push(`${c.Country},${c.Gold},${c.Silver},${c.Bronze},${c.Total}`);
  }

  return lines.join("\n");
}