#include "leetcode.h" class Solution { public: int minDeletions(string s) { vector freq(26, 0); int ans = 0; for (char c : s) freq[c - 'a']++; sort(freq.begin(), freq.end()); for (int i = 24; i >= 0; i--) { if (freq[i] == 0) break; if (freq[i] >= freq[i + 1]) { int prev = freq[i]; freq[i] = max(0, freq[i + 1] - 1); ans += prev - freq[i]; } } return ans; } }; int main() { Solution obj; string s = "aab"; cout << obj.minDeletions(s); }