priority_queue member function

没有优先队列的dijkstra不算真的dijkstra

所以我又回来补常识了

<1>priority_queue::emplace

<7>priority_queue::top

 // priority_queue::emplace
 #include <iostream>       // std::cout
 #include <queue>          // std::priority_queue
 #include <string>         // std::string

 int main ()
 {
   std::priority_queue<std::string> mypq;

   mypq.emplace("orange");
   mypq.emplace("strawberry");
   mypq.emplace("apple");
   mypq.emplace("pear");

   std::cout << "mypq contains:";
   while (!mypq.empty())
   {
      std::cout << ' ' << mypq.top();
      mypq.pop();
   }
   std::cout << '\n';

   return ;
 }
 //Ooutput:mypq contains: strawberry pear orange apple

<2>priority_queue::empty

<3>priority_queue::pop

<4>priority_queue::push

 // priority_queue::push/pop
 #include <iostream>       // std::cout
 #include <queue>          // std::priority_queue

 int main ()
 {
   std::priority_queue<int> mypq;

   mypq.push();
   mypq.push();
   mypq.push();
   mypq.push();

   std::cout << "Popping out elements...";
   while (!mypq.empty())
   {
      std::cout << ' ' << mypq.top();
      mypq.pop();
   }
   std::cout << '\n';

   return ;
 }
 //Output:Popping out elements... 100 40 30 25

<5>priority_queue::size

<6>priority_queue::swap

 // priority_queue::swap
 #include <iostream>       // std::cout
 #include <queue>          // std::priority_queue

 int main ()
 {
   std::priority_queue<int> foo,bar;
   foo.push (); foo.push(); foo.push();
   bar.push (); bar.push();

   foo.swap(bar);

   std::cout << "size of foo: " << foo.size() << '\n';
   std::cout << "size of bar: " << bar.size() << '\n';

   return ;

 /*Output:
 size of foo: 2
 size of bar: 3*/

然后还有个自定义排序来着，到时候再摸。