https://www.acgo.cn/

#include<iostream>
using namespace std;
int main() {
int n;
cin >> n;
int size = 2 * n - 1;
for (int i = 0; i < size; i++) {
for (int j = 0; j < size; j++) {
int dis = abs(i-(n-1));
if (j == dis || j == (size - 1 - dis) || (i == 0 && j == n - 1) || (i == size - 1 && j == n - 1)) {
cout << "";
}
else {
cout << " ";
}
}
cout << endl;
}
return 0;
}
/

   _____
   |_ _|

n (O O) n
H |_/| H
nHnn/ _/ \nnHn
<V VV / \ VV V>
__/| |//
*/