1
var maxUniqueSplit = function (s) {
2
  let wordSet = new Set(),
3
    res = 1;
4

5
  function checkUniqueSubstring(i) {
6
    if (i === s.length) {
7
      res = Math.max(wordSet.size, res);
8
      return;
9
    }
10

11
    for (let j = i + 1; j <= s.length; j++) {
12
      let str = s.substring(i, j);
13
      if (!wordSet.has(str)) {
14
        wordSet.add(str);
15
        checkUniqueSubstring(j);
16
        wordSet.delete(str);
17
      }
18
    }
19
  }
20

21
  checkUniqueSubstring(0);
22

23
  return res;
24
};