骑士的金币：计算骑士在N天内获得的总金币数

#include

int main() { int days; std::cin >> days;

int coins = 0;
int current = 1;
int count = 1;

for (int i = 1; i <= days; i++) {
    coins += current;
    count--;

    if (count == 0) {
        current++;
        count = current;
    }
}

std::cout << coins << std::endl;

return 0;

}