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Challenge 132: Purge Most Frequent

curriculum/challenges/english/blocks/daily-coding-challenges-javascript/691f7773cddba1caf1bf5ecb.md

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--description--

Given an array of values, remove all occurrences of the most frequently occurring element and return the resulting array.

  • If multiple values are tied for most frequent, remove all of them.
  • Do not change any of the other elements or their order.

--hints--

purgeMostFrequent([1, 2, 2, 3]) should return [1, 3].

js
assert.deepEqual(purgeMostFrequent([1, 2, 2, 3]), [1, 3]);

purgeMostFrequent(["a", "b", "d", "b", "c", "d", "c", "d", "c", "d"]) should return ["a", "b", "b", "c", "c", "c"].

js
assert.deepEqual(purgeMostFrequent(["a", "b", "d", "b", "c", "d", "c", "d", "c", "d"]), ["a", "b", "b", "c", "c", "c"]);

purgeMostFrequent(["red", "blue", "green", "red", "blue", "green", "blue"]) should return ["red", "green", "red", "green"].

js
assert.deepEqual(purgeMostFrequent(["red", "blue", "green", "red", "blue", "green", "blue"]), ["red", "green", "red", "green"]);

purgeMostFrequent([5, 5, 5, 5]) should return [].

js
assert.deepEqual(purgeMostFrequent([5, 5, 5, 5]), []);

purgeMostFrequent([10, 12, 7, 3, 7, 7, 12, 12]) should return [10, 3].

js
assert.deepEqual(purgeMostFrequent([10, 12, 7, 3, 7, 7, 12, 12]), [10, 3]);

--seed--

--seed-contents--

js
function purgeMostFrequent(arr) {

  return arr;
}

--solutions--

js
function purgeMostFrequent(arr) {
  const freq = {};
  for (const val of arr) {
    freq[val] = (freq[val] || 0) + 1;
  }

  const maxFreq = Math.max(...Object.values(freq));

  const toRemove = new Set(
    Object.keys(freq).filter(key => freq[key] === maxFreq)
  );

  return arr.filter(val => !toRemove.has(String(val)));
}