1.3.cc

//Time: n^2 Space: 0
void RemoveDuplicate(char* str) {
  char* tail = str;
  char* p1 = str;
  char* p2 = str;

  while (*p2 != '\0') {
    for (p1 = str; p1 < tail; ++p1) {
      if (*p2 == *p1) break;
    }
    if (p1 == tail) *(tail++) = *p2;
    ++p2;
  }
  *tail = *p2;
}

//Time: n Space: 256
void RemoveDuplicate1(char* str) {
  bitset<256> hit;
  char* tail = str;
  while (*str != '\0') {
    if (!hit[*str]) {
      hit[*str] = true;
      *tail = *str;
      ++tail;
    }
    ++str;
  }
  *tail = '\0';
}