// 1647. Minimum Deletions to Make Character Frequencies Unique #include #include #include /* * a string 's' is called good if there are no two different characters in 's' * that have the same frequency. given a string 's', return the minimum number * of characters you need to delete to make 's' good. the frequency of a * character in a string is the number of times it appears in the string. for * example, in the string "aab", the frequency of 'a' is 2, while the frequency * of 'b' is 1. */ int cmp(const int *a, const int *b) { return (*b - *a); } int minDeletions(char *s) { int n = strlen(s), ans[26] = {}, cnt = 0; for (int i = 0; s[i] != '\0'; i++) ans[s[i] - 'a']++; qsort(ans, 26, sizeof(int), cmp); for (int i = 1; i < 26; i++) { if (!ans[i]) continue; while (ans[i] >= ans[i - 1]) { cnt++; ans[i]--; if (!ans[i]) break; } return cnt; } } int main() { char s1[] = {"aab"}, s2[] = {"aaabbbcc"}, s3[] = {"ceabaacb"}; printf("%d\n", minDeletions(s1)); // expect: 0 printf("%d\n", minDeletions(s2)); // expect: 2 printf("%d\n", minDeletions(s3)); // expect: 2 }