hash_table.cpp

#include <iostream>
#include <unordered_set>

struct Node {
  std::string product_name;
  int color;
  int size;
  bool operator==(const Node &other) const {
    return product_name == other.product_name && color == other.color && size == other.size;
  }
};

template <> struct std::hash<Node> {
  size_t operator()(const Node &key) const {
    size_t h1 = std::hash<std::string> {} (key.product_name);
    size_t h2 = std::hash<int> {} (key.color);
    size_t h3 = std::hash<int> {} (key.size);
    return h1 ^ (h2 << 1) ^ (h3 << 2);
  }
};

int main() {
  std::unordered_set<Node> set;
  char query;
  std::string name;
  int color;
  int size;
  while(std::cin >> query >> name >> color >> size) {
    Node _new;
    _new.product_name = name;
    _new.color = color;
    _new.size = size;
    switch(query) {
      case '+':
        if(set.insert(_new).second)
          std::cout << "OK\n";
        else
          std::cout << "FAIL\n";
        break;
      case '-':
        if(set.erase(_new))
          std::cout << "OK\n";
        else
          std::cout << "FAIL\n";
        break;
      case '?':
        if(set.count(_new))
          std::cout << "OK\n";
        else
          std::cout << "FAIL\n";
    }
  }
}