Codeforces•Apr 08, 2025
Soldier and Bananas
Hazrat Ali
Codeforces
A soldier wants to buy w bananas in the shop. He has to pay k dollars for the first banana, 2k dollars for the second one and so on (in other words, he has to pay i·k dollars for the i-th banana).
He has n dollars. How many dollars does he have to borrow from his friend soldier to buy w bananas?
Input
The first line contains three positive integers k, n, w (1 ≤ k, w ≤ 1000, 0 ≤ n ≤ 109), the cost of the first banana, initial number of dollars the soldier has and number of bananas he wants.
Output
Output one integer — the amount of dollars that the soldier must borrow from his friend. If he doesn't have to borrow money, output 0.
Examples
Input
3 17 4
Output
13
Solution
#include<stdio.h>
int main()
{
long long int starting_price,money,amount,cost=0;
scanf("%lld%lld%lld",&starting_price,&money,&amount);
for(int i=1; i<=amount; i++)
{
cost+=starting_price*i;
}
if(cost<=money)
printf("0");
else
printf("%lld",cost-money);
}