1015 B | 1015 chars
#include <bits/stdc++.h>
#define for1(s,n) for(int i = s; i < n; i++)
#define for1j(s,n) for(int j = s; j < n; j++)
#define foreach(k) for(auto i : k)
#define foreachj(k) for(auto j : k)
#define pb(a) push_back(a)
#define sz(a) a.size()
using namespace std;
typedef unsigned long long ull;
typedef long long ll;
typedef vector <int> iv1;
typedef vector <vector<int>> iv2;
typedef vector <ll> llv1;
typedef unsigned int uint;
typedef vector <ull> ullv1;
typedef vector <vector <ull>> ullv2;
ll N;
int D[550][550];
void f(int Y, int N) {
if(N<0) return;
f(Y+2, N-1);
for(int i=Y; i<=Y+4*(N-1); i++) {
D[i][Y] = 1;
D[Y][i] = 1;
D[i][Y+4*(N-1)] = 1;
D[Y+4*(N-1)][i] = 1;
}
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> N;
f(1,N);
for(int y=1; y<=4*(N-1)+1; y++) {
for(int x=1; x<=4*(N-1)+1; x++) {
if(D[y][x]) cout << "*";
else cout << " ";
}
cout << "\n";
}
}