Permutations

#include<bits/stdc++.h>
using namespace std;
    void display(vector<int> & vec)
    {
    for (int i = 0; i < vec.size(); i++)
    {
        cout<<vec[i]<<" ";
    }
    }

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    int n;
    cin>>n;

    if(n==1){
        cout<<1<<endl;
    }


    vector<int> vec,v1,v2;
    for (int i = 1; i <= n; i++)
    {
        if(i%2!=0)
        {
            v1.push_back(i);
        }
        else{
            v2.push_back(i);
        }
    }

    for(int i=v2.size()-1; i>=0;i--){
        vec.push_back(v2[i]);
    }
    for(int i=v1.size()-1; i>=0;i--){
        vec.push_back(v1[i]);
    }

    for (int i = 0; i < vec.size()-1; i++)
    {
        if(abs(vec[i]-vec[i+1])==2)
        {
            display(vec);
            break;
        }
        else{
            cout<<"NO SOLUTION"<<endl;
            break;
        }
    }


return 0;
}