A_Stable_Arrangement_of_Rooks.cpp

#include<bits/stdc++.h>
using namespace std;
#define ll long long int
#define pb push_back
#define mp make_pair
#define F first
#define S second
#define tr(it, a) for(auto it = a.begin(); it != a.end(); it++)
#define fo(i,n) for(ll i=0;i<n;i++)
#define fo1(i,n) for(ll i=1;i<=n;i++)
#define all(v) v.begin(), v.end()
#define sortall(v) sort(all(v))
#define sortalld(v) sort(all(v),greater<ll>())
typedef pair<int, int>	pii;
typedef pair<ll, ll>	pl;
typedef vector<int> veci;
typedef vector<ll>  vecll;
typedef vector<pii>		vpii;
typedef vector<pl>		vpl;
const int mod = 1000000007;
int pow(int base, int exp) {base %= mod;int result = 1;while (exp > 0) {if (exp & 1) result = ((ll)result * base) % mod;base = ((ll)base * base) % mod;exp >>= 1;}return result;}
int T, P, Q, R, X, Y, U, V, N,M;
ll t, p, q, r, x, y, u, v, n, m,k;
int main() {
    ios_base::sync_with_stdio(0);
    cin>>t;
    while(t--)
    {
        cin>>n>>k;

        if(k>ceil(n/2.0))
            {cout<<-1<<endl;
        continue;}
        else{
            fo(i,n)
            {
                fo(j,n)
                {
                    if(i==j && i==0 && k!=0)
                       { cout << "R";
                    k--;}
                    else if (i == j && i == n - 1 & k != 0)
                         {   cout<< "R";
                    k--;}
                    else if (i == j  && k != 0 && n>=5 && i%2==0)
                         {   cout<< "R";
                    k--;}
                    else cout << ".";
                }
                cout << endl;
            }
        }
    }
 
    

    
}
// string.find("xyz") !=string::npos  //if xyz is found