这题用最小堆来解过不了吗

#include<iostream>
#include<algorithm>
using namespace std;
struct Heap{
	int* heap;
	int n;
};
int leftchild(int pos)
{return 2*pos+1;}
int rightchild(int pos) 
{return 2*pos+2;}
void siftdown(Heap *h,int pos){
  	while(!((pos>=(h->n)/2)&&(pos<h->n))){
   	    int j=leftchild(pos); 
    	int rc=rightchild(pos);
   		if(rc<h->n && h->heap[rc]<h->heap[j]) j=rc;
   		if(h->heap[pos]<h->heap[j]) return;
   		swap(h->heap[pos],h->heap[j]);
   		pos=j;	
	}
}

void remove(Heap* h){
	swap(h->heap[0],h->heap[--h->n]);
	if(h->n!=0) siftdown(h,0);
}
void buildheap(Heap* h){
	for(int i=(h->n)/2-1;i>=0;i--) siftdown(h,i);
}
int main(){
	int n;
	int k;
	cin>>n;
	cin>>k;
	int *arr=new int[n];
	for(int i=0;i<n;++i) cin>>arr[i];
	Heap h;
	h.heap=arr;
	h.n=n;
	buildheap(&h);
	for(int i=0;i<k;++i) remove(&h);
	cout<<h.heap[0];
}