stl priority_queue

1.優先級隊列，是一個容器適配器。實際就是在一個堆上進行的插入和讀取操作，並保證時時刻刻是一個堆






//_C: 系統默認用vector做容器
_Pr:  用於內部堆的重新構造(插堆和出堆的判斷謂詞以決定是大根堆還是小根堆,默認是大根堆)


template<class _Ty, class _C = vector<_Ty>,
class _Pr = less<_C::value_type> >
class priority_queue {
public:
typedef _C::allocator_type allocator_type;
typedef _C::value_type value_type;
typedef _C::size_type size_type;
explicit priority_queue(const _Pr& _X = _Pr(),
const allocator_type& _Al = allocator_type())
: c(_Al), comp(_X) {}
typedef const value_type *_It;
priority_queue(_It _F, _It _L, const _Pr& _X = _Pr(),
const allocator_type& _Al = allocator_type())
: c(_Al), comp(_X)
{for (; _F != _L; ++_F)
push(*_F); }
allocator_type get_allocator() const
{return (c.get_allocator()); }
bool empty() const
{return (c.empty()); }
size_type size() const
{return (c.size()); }
value_type& top()
{return (c.front()); }
const value_type& top() const
{return (c.front()); }
void push(const value_type& _X)
{c.push_back(_X);
push_heap(c.begin(), c.end(), comp); }
void pop()
{pop_heap(c.begin(), c.end(), comp);
c.pop_back(); }
protected:
_C c;
_Pr comp;
};






2.優先級隊列不支持複製等操作,需要包括頭<queue>