堆排序#1#2WA求助

#include<iostream>
using namespace std;
const int inf=1234567890;
int n,a[5000010],x,i,k;
void put(int d){
    int now,next;
    a[i]=d;
    now=i;
    while(now>1){
        next=now>>1;
        if(a[now]>=a[next]) return;
        swap(a[now],a[next]);
        now=next;           
    }
}
void mypro(int k){
    if(!a[2*k]&&!a[2*k+1]) a[k]=0;
    else if(!a[2*k+1]&&a[2*k]) a[k]=a[2*k],mypro(2*k);
    else if(!a[2*k]&&a[2*k+1]) a[k]=a[2*k+1],mypro(2*k+1);
    else if(a[2*k]<a[2*k+1]){
        a[k]=a[2*k];
        mypro(2*k);
    }
    else{
        a[k]=a[2*k+1];
        a[2*k+1]=0;
        mypro(2*k+1);   
    }
}
int main(){
    cin>>n>>k;
    for(i=1;i<=n;i++) scanf("%d",&x),put(x);
    while(k--){
        a[1]=inf;
        mypro(1);
    }
    cout<<a[1];
    return 0;
}