急，谁能回一下啊

#include<iostream>
using namespace std;
int main(){    
    int a[20]={2,4,8,16,32,64,128,256,512,1024,2048,4096,8192,16384,32768,65536,131072,262144,524288,1048576};
    int n;
    cin>>n;
    if (n%2==0 and n!=0){
        for (int i=18;i<=n;--i){
            if (a[i]<n){
                cout<<a[i]<<" ";
            }
            else if (a[i]==n){
                cout<<a[i];
            }
        }
    }
    else{
        cout<<"-1";
    }
    return 0;
}