优先队列是单向队列的一种，可以按照默认或自定义的一种方式来对队列中的数据进行动态排序

template
     
      , class _Pr = less
      
        > //默认以vector为容器的  class priority_queue  {   // priority queue implemented with a _Container  public:      typedef _Container container_type;      typedef typename _Container::value_type value_type;      typedef typename _Container::size_type size_type;      typedef typename _Container::reference reference;      typedef typename _Container::const_reference const_reference;        priority_queue() : c(), comp()      {   // construct with empty container, default comparator      }        explicit priority_queue(const _Pr& _Pred) : c(), comp(_Pred)      {   // construct with empty container, specified comparator      }        priority_queue(const _Pr& _Pred, const _Container& _Cont) : c(_Cont), comp(_Pred)      {   // construct by copying specified container, comparator          make_heap(c.begin(), c.end(), comp); //参见《STL系列之四 heap 堆的相关函数》      }        template
       
              priority_queue(_Iter _First, _Iter _Last) : c(_First, _Last), comp()      {   // construct by copying [_First, _Last), default comparator          make_heap(c.begin(), c.end(), comp);      }        template
        
               priority_queue(_Iter _First, _Iter _Last, const _Pr& _Pred) : c(_First, _Last), comp(_Pred)      {   // construct by copying [_First, _Last), specified comparator          make_heap(c.begin(), c.end(), comp);      }        template
         
                priority_queue(_Iter _First, _Iter _Last, const _Pr& _Pred, const _Container& _Cont) : c(_Cont), comp(_Pred)      {   // construct by copying [_First, _Last), container, and comparator          c.insert(c.end(), _First, _Last);          make_heap(c.begin(), c.end(), comp);      }        bool empty() const      {   // test if queue is empty          return (c.empty());      }        size_type size() const      {   // return length of queue          return (c.size());      }        const_reference top() const      {   // return highest-priority element          return (c.front());      }        reference top()      {   // return mutable highest-priority element (retained)          return (c.front());      }        void push(const value_type& _Pred)      {   // insert value in priority order          c.push_back(_Pred);          push_heap(c.begin(), c.end(), comp);      }        void pop()      {   // erase highest-priority element          pop_heap(c.begin(), c.end(), comp);          c.pop_back();      }    protected:      _Container c;   // the underlying container      _Pr comp;   // the comparator functor  };
         
        
       
      
     

　　

用法：

1、默认用<运算符进行排序

大的先输出

 

2、priority_queue<type, vector<type>, fun<type>>pq;

vector<type>为容器类型

fun<type>为比较函数

 

3、自定义优先级

重载<

struct node{    friend bool operator< (node n1, node n2)    {        return n1.priority < n2.priority;    }    int priority;    int value;};