void push(const value_type& x);
Effects: As if by:
c.push_back(x); push_heap(c.begin(), c.end(), comp);
void push(value_type&& x);
c.push_back(std::move(x)); push_heap(c.begin(), c.end(), comp);
template <class... Args> void emplace(Args&&... args)
c.emplace_back(std::forward<Args>(args)...); push_heap(c.begin(), c.end(), comp);
void pop();
pop_heap(c.begin(), c.end(), comp); c.pop_back();