heap实现优先队列priority_queue

#include
using namespace std;

const int maxn=1e3+10;
struct priority_queue{
	int data[maxn];
	int size;
	priority_queue(){
		size=0;
	}
	void heap_up(int id) {
	if (id == 1)return;
	if (heap[id] > heap[id / 2]) {
		swap(heap[id], heap[id / 2]);
		heap_up(id / 2);
		}
	}
	void add(int v) {
		heap[++heapsize] = v;
		heap_up(heapsize);
	}
	int top() {
		return heap[1];
	}
	void heap_down(int id) {
		if (id * 2 > heapsize)return;
		int k = id;
		if (heap[id * 2] > heap[k])k = id * 2;
		if (id * 2 + 1 <= heapsize && heap[id * 2 + 1] > heap[k])k = id * 2 + 1;
		if (k == id)return;
		swap(heap[k], heap[id]);
		heap_down(k);
	}
	void pop() {
		heap[1] = heap[heapsize];
		heapsize--;
		heap_down(1);
	}
};
int main(){
	priority_queue ans;
	for(int i=1;i<=10;i++){
		ans.push(i);
	}
	cout<<ans.top()<<endl;
	ans.pop();
	cout<<ans.top()<<endl;
	ans.pop();ans.pop();
	cout<<ans.top()<<endl;
	ans.push(220);
	cout<<ans.top()<<endl;
	
}