#include <iostream>
#include <string>
#include <algorithm>
#include <numeric>
#include <vector>
using namespace std;
int main() {
int n = 10;
auto print_row = [&n](int i) {
int spaces = abs(i);
int stars = 2 * (n - spaces) - 1;
cout << string(spaces, ' ') << string(stars, '*') << endl;
};
vector<int> rows(2 * n - 1);
iota(rows.begin(), rows.end(), -n + 1);
for_each(rows.begin(), rows.end(), print_row);
return 0;
}