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 << '
';

  return 0;
}
//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(30);
  mypq.push(100);
  mypq.push(25);
  mypq.push(40);

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

  return 0;
}
//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 (15); foo.push(30); foo.push(10);
  bar.push (101); bar.push(202);

  foo.swap(bar);

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

  return 0;

/*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。