S002-AC.cc 614 Bytes
#include <iostream>
#include <string>

using namespace std;

int main()
{
	int n,spaces,ast = 1;
	cin >> n;
	if(n == 1)
	{
		cout << "*" << endl;
		return 0;
	}
	spaces = n-1;
	while(1)
	{
		for(int j = spaces; j > 0; j--)
		{
			cout << " ";
		}
		for(int k = ast; k > 0; k--)
		{
			cout << "*";
		}
		cout << endl;
		if(!spaces)
		{
			break;
		}
		spaces--;
		ast += 2;
	}
	ast -= 2;
	spaces++;
	while(1)
	{
		for(int j = spaces; j > 0; j--)
		{
			cout << " ";
		}
		for(int k = ast; k > 0; k--)
		{
			cout << "*";
		}
		cout << endl;
		if(ast == 1)
		{
			break;
		}
		spaces++;
		ast -= 2;
	}
	return 0;
}