1793B - Fedya and Array - CodeForces Solution

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define f(x, a, b) for (int x = a; x < b; x++)

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int t=1;
    cin >> t;
    while (t--)
    {
        int x,y;
        cin>>x>>y;
        cout<<2*(x-y-1)+2<<"\n";
        for(int i=y;i<=x;i++){
            cout<<i<<" ";
        }
        for(int i=x-1;i>=y+1;i--){
            cout<<i<<" ";
        }
    cout<<endl;
 
    }

    return 0;
}