Minimum Deletions to Make Character Frequencies Unique LeetCode solution in Java

1
class Solution {
2
  private int N = 26;
3

4
  public int minDeletions(String s) {
5
    int[] array = new int[N];
6
    for (char ch : s.toCharArray()) {
7
      array[ch - 'a']++;
8
    }
9
    int ans = 0;
10
    Set<Integer> set = new HashSet<>();
11
    for (int i : array) {
12
      if (i == 0) continue;
13
      while (set.contains(i)) {
14
        i--;
15
        ans++;
16
      }
17
      if (i != 0) {
18
        set.add(i);
19
      }
20
    }
21
    return ans;
22
  }
23
}