triangle.cpp

#include <iostream>
#include <vector>

using namespace std;

int main() {
	int a;
	cin >> a;
	int phase = 0;
	vector<bool>star;
	for (int x = 0; x < a*2+10; x++) {
		star.push_back(0);
	}
	star[0] = 1;
	for (int i = 0; i < a; i++) {
		for (int p = 0; p < a - i; p++) {
			cout << " ";
		}
		for (int p = 0; i != 0&& p < i * 2 + 1;) {
			if (star[p]) {
				if (!star[p + 2]) {
					star[p + 2] = 1;
					p += 6;
				}
				else {
					if (!star[p + 1]) {
						star[p + 1] = 1;
						star[p + 3] = 1;
						star[p + 4] = 1;
						p += 6;
					}
					else {
						int z = p;
						for (int q = 6; q+p < a*2+1; q+=6) {
							if (star[p+q])z = q+p;
							else break;
						}
						for (int n = p + 1; n < z + 6; n++) {
							star[n] = 0;
						}
						if(z+6<a*2+1)star[z + 6] = 1;
						if(z+12<a*2+1)p = z + 12;
						else break;
					}
				}
			}
			else {
				p += 6;
			}
		}
		for (int p = 0; p < i * 2 + 1; p++) {
			if (star[p])cout << "*";
			else cout << " ";
		}
		cout << endl;
	}
}

/*
10000
10100
11111 3 6*1-1
10000010000 0 6
10100010100
11111011111 11 = 6*2-1
10000000000010000000000 0 12
10100000000010100000000 
11111000000011111000000
10000010000010000010000
10100010100010100010100
11111011111011111011111 23 = 6*4-1

*/