/*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) ;}