题解

#include <iostream>
using namespace std;
int main(){
int n,i=2,j=1,m=1;
cin>>n;
while(n>0)
{
n--;
if(m%2==1)
{
cout<<i<<" ";
i+=2;
}
else
{
cout<<j<<" ";
j+=2;
}
m++;
}
printf("\n");
return 0;
}