help in c++,i have mention the location of error

Question

input are
5
2000000
1000000
2
3
1000000
4
error is ocurring in bool a[1000005] if i make bool a[2000005] it works
#include <iostream>
using namespace std;
int printhi(int ar[], int k,int n)
{ bool a[1000005]={0};int temp;//if i make 2000005 it works
for(int i=0;i<n;i++)
{ temp=k-ar[i];
if(temp>=0&&a[temp]==1)
{cout<<"YES";
return 0;
}
a[ar[i]]=1;
}
cout<<"NO";
return 0;
}
int main() {
int n,k;
cin>>n>>k;
int ar[n];
for(int i=0;i<n;i++)cin>>ar[i];
printhi(ar,k,n);

}

Answer 1

index out of range, here's why:
k = 2000000

temp= k(2000000) - ar[1](2) = 1999998

a[temp (1999998)] is out of index
this is causing the problem

Answer 2

thanku Sreejith