2091 空心三角形

比较简单，算好空格的规律即可，就是格式比较坑，最后一个三角形之后不能有空行。

#include<iostream> using namespace std; int main() { char c; int n,flag=0; while (cin >> c) { if (c == '@') break; else if(flag) cout << endl; cin >> n; for (int i = 1; i <n; ++i) { for (int j = 1; j <= n - i; ++j) cout << ' '; cout << c; for (int j = 1; j <= 2*i - 3; ++j) cout << ' '; if(i!=1) cout << c << endl; else cout << endl; } for (int i = 1; i <= 2 * n - 1; ++i) { cout << c; flag = 1; } cout << endl; } return 0; }