LeetCode: Minimum Number Of People To Teach Solution

1function intersection(setA, setB) {
2  let _intersection = new Set()
3  for (let elem of setB) {
4    if (setA.has(elem)) {
5      _intersection.add(elem)
6    }
7  }
8  return _intersection
9}
10
11var minimumTeachings = function (n, languages, friendships) {
12  languages = languages.map(l => new Set(l))
13  const conflictUsers = new Set()
14  for (let [i, j] of friendships) {
15    if (!intersection(languages[i - 1], languages[j - 1]).size) {
16      conflictUsers.add(i - 1)
17      conflictUsers.add(j - 1)
18    }
19  }
20  const languageCount = Array(n).fill(0)
21  for (const user of conflictUsers) {
22    for (const language of languages[user]) {
23      languageCount[language - 1]++
24    }
25  }
26  return conflictUsers.size - Math.max.apply(null, languageCount)
27}