[C++] Multiple key with unique property (implemented by STL:map)

晚上跟小強談論到如何實做Multiple keys with unique property problem. (implemented by STL:map),紀錄一下。
My source code from gist

#include <iostream>
#include <map>
using namespace std;

class object ;
class object
{
  public:
      static int count;
      int value1;
      int value2;
int value3;
int value4;
      object():value1(0),value2(0),value3(0),value4(0)
      {
          ++object::count;
      }

      object(int a, int b,int c,int d): value1(a),value2(b),value3(c),value4(d)
      {
          cout << "(" << a << "," << b << "," << c << "," << d << ")" << endl;
          ++object::count;
      }

      object(const object & objectA):value1(objectA.value1),value2(objectA.value2),value3(objectA.value3),value4(objectA.value4)
      {

      }

      object & operator = (const object & objectA)
      {
          this->value1=objectA.value1;
          this->value2=objectA.value2;
    this->value3=objectA.value3;
    this->value4=objectA.value4;
          return *this;
      }
};
int object::count=0;

class Mycmp
{
  public:
      bool operator()(const object & A,const object & B) const
      {
          //return !((A.value1==B.value1) && (A.value2==B.value2));
    return (A.value1<B.value1) || (A.value2<B.value2) || (A.value3<B.value3) || (A.value4<B.value4);
      }
};

int main(int argc , char * argv[])
{
  cout << "INPUT:" << endl;
  /* Set input information */
  object objectA(1,2,1,3),
         objectB(2,2,1,3),
         objectC(3,2,1,2),
         objectD(3,2,1,2),
         objectE(1,3,0,3),
         objectF(1,3,1,1),
         objectG(2,1,1,1),
         objectH(3,2,1,8),
         objectI(2,1,2,7),
   objectJ(2,1,1,1),
   objectK(2,2,0,8),
   objectL(2,2,1,3);
  cout << "INTPUT SIZE:" << object::count << endl;

  map<object,int,Mycmp> MyMap;
  MyMap.insert(pair<object,int>(objectA,1));
  MyMap.insert(pair<object,int>(objectB,2));
  MyMap.insert(pair<object,int>(objectC,2));
  MyMap.insert(pair<object,int>(objectD,2));
  MyMap.insert(pair<object,int>(objectE,2));
  MyMap.insert(pair<object,int>(objectF,2));
  MyMap.insert(pair<object,int>(objectG,2));
  MyMap.insert(pair<object,int>(objectH,2));
  MyMap.insert(pair<object,int>(objectI,2));
  MyMap.insert(pair<object,int>(objectJ,2));
  MyMap.insert(pair<object,int>(objectK,2));
  MyMap.insert(pair<object,int>(objectL,2));
  cout << "AFTER INSERT INFORMATION:" << endl;
  for(map<object,int>::iterator it = MyMap.begin(); it!=MyMap.end() ; ++it)
  {
      cout << "(" << it->first.value1 << ","  << it->first.value2 << ","  << it->first.value3 << "," << it->first.value4 << ")" << endl;
  }
  cout << "INSERT SIZE:" << MyMap.size() << endl ;
  return 0;
}

輸出結果：

INPUT:

(1,2,1,3)

(2,2,1,3)

(3,2,1,2)

(3,2,1,2)

(1,3,0,3)

(1,3,1,1)

(2,1,1,1)

(3,2,1,8)

(2,1,2,7)

(2,1,1,1)

(2,2,0,8)

(2,2,1,3)

INTPUT SIZE:12

AFTER INSERT INFORMATION:

(2,2,0,8)

(2,1,1,1)

(2,2,1,3)

(2,1,2,7)

(1,3,1,1)

(1,3,0,3)

(3,2,1,2)

(1,2,1,3)

(2,2,1,3)

(3,2,1,8)

INSERT SIZE:10

補充：

上述的 operator () ，對C++不太熟的讀者應該很陌生。(就連我自己也第一次見到，可能是我之前大多是寫operator +,<<,= 為主的功能)

其實他的執行方式大約如下：

 MyCmp objectCmp;
 bool check=objectCmp(objectA,objectB);    /* Using () operator! */

那些Operator加起來都可以去實做代數學的+,* 等運算了。
想要知道更多operator，請按此。