Alternating Characters HackerRank - Refreshing C knowledge - return an integer representing the minimum number of deletions to make the alternating string.

alternating_characters.c

int alternatingCharacters(char* s) {
    int c = 0;
    char* AB = "AB";
    char* BA = "BA";
    char *ptr1 = strstr(s, AB);
    char *ptr2 = strstr(s, AB);
    if (ptr1 != NULL || ptr2 != NULL)
    {
      for (int i = 0; i < strlen(s) - 1; i++) {
        if (s[i] == s[i + 1]) {
          c += 1;
        }
      }
      return c;
    }
    else
    {
        return strlen(s) - 1;
    }
}