大顶堆

#include <iostream>
#include <algorithm>
#include <stdio.h>
using namespace std;
class Heap{
private:
	int r[100],length;
public:
    //初始化堆
	Heap(int n){
		length = n;
		for(int i = 0 ; i < n ; i++)
			cin>>r[i];
	}
	//向下检查，若子节点大于父节点，则交换
	void SiftHeap (int now , int n){
		int i,j;
		i = now ; j = i * 2 + 1;
		while(j < n){
			if(j < n - 1 && r[j] < r[j+1]) j++;
			if(r[i] > r[j])break;
			else{
				swap(r[i],r[j]);
				i = j ; j = j * 2 + 1;
			}
		}
	}
    //建堆
	void BuildHeap(){
		for(int i = (length - 1)/2 ; i >= 0 ; i--)
			SiftHeap(i,length);
	}
    //添加一个元素后恢复大顶堆
	void Addone(int newval){
		r[length++]=newval;
		int i,j;i=length-1,j=(i+1)/2 - 1;
		while(i>=0){
			if(r[j]>r[i])break;
			else{
				swap(r[i],r[j]);
				i=j;j=(j+1)/2 -1;
			}
		}
	}
	//删除一个元素后恢复大顶堆
	void Deleteone(int pos){
        swap(r[pos],r[--length]);
        int i,j;
        i = pos; j = (i+1)/2 -1;
        while(r[i]>r[j]){
            swap(r[i],r[j]);
            i = j; j = (j+1)/2 -1;
        }
        SiftHeap(pos,length);
	}
	//显示详细信息
	void show(){
		for(int i = 0 ; i < length; i++)cout<<r[i]<<" ";
		puts("");
	}
};
int main(){
	int n,tmp;
	cin>>n;
	Heap h(n);
	h.BuildHeap();
	h.show();

	cout<<"insert a number"<<endl;
	cin>>tmp;
	h.Addone(tmp);
	h.show();

	cout<<"delete a number at position"<<endl;
	cin>>tmp;
	h.Deleteone(tmp);
	h.show();

	return 0;
}