Programmers 82612

부족한 금액 계산하기

using namespace std;
typedef long long ll;

long long solution(int price, int money, int count)
{
    ll answer = 0;
    
    ll sum = 0;
    
    for (int i = 1; i <= count; i++)
    {
        sum += (ll)i * (ll)price;
    }
    
    if (sum - money > 0) answer = sum - (ll)money;

    return answer;
}