小根堆

 /*小根堆*/
class Heap{
   private :
      int   num[1008] ;
      int   N ;
   public :
      void  push(int) ;
      int   top() ;
      void  pop() ;
      void  up(int) ;
      void  down(int) ;
      int   empty_() ;
            Heap() ;
};

Heap::Heap(){
    N = 0 ;
}

int Heap::top(){
    return num[1] ;
}

int Heap::empty_(){
    return N < 1 ;
}

void Heap::down(int id){
    int Lson = id<<1 ;
    int Rson = id<<1|1 ;
    int next = id ;
    if(Lson <= N && num[Lson] < num[next])
        next = Lson ;
    if(Rson <= N && num[Rson] < num[next])
        next = Rson ;
    if(next != id){
        swap(num[id],num[next]) ;
        down(next) ;
    }
}

void Heap::up(int id){
    int father = id>>1 ;
    if(father >=1 && num[id] < num[father]){
        swap(num[id],num[father]) ;
        up(father) ;
    }
}

void Heap::pop(){
    swap(num[N],num[1]) ;
    N-- ;
    down(1) ;
}

void Heap::push(int x){
    num[++N] = x ;
    up(N) ;
}