题解 | #金字塔#

找规律，代码如下

#include <iostream>

using namespace std;

int main() {
  int n;
  while (cin >> n) {
    for (int i = 1; i <= n; i++) {
      for (int j = 1; j <= 2*n-1; j++) 
	if (j >= n-i+1 && j <= n+i-1) cout << '*';
	else cout << ' ';
      cout << endl;
    }
  }
  return 0;
}