Baskets of Gold Coins 2401

Problem Description

You are given N baskets of gold coins. The baskets are numbered from 1 to N. In all except one of

the baskets, each gold coin weighs w grams. In the one exceptional basket, each gold coin weighs

w-d grams. A wizard appears on the scene and takes 1 coin from Basket 1, 2 coins from Basket 2,

and so on, up to and including N-1 coins from Basket N-1. He does not take any coins from

Basket N. He weighs the selected coins and concludes which of the N baskets contains the lighter

coins. Your mission is to emulate the wizard's computation.

Input

The input file will consist of one or more lines; each line will contain data for one instance of the

problem. More specifically, each line will contain four positive integers, separated by one blank

space. The first three integers are, respectively, the numbers N, w, and d, as described above. The

fourth integer is the result of weighing the selected coins.

N will be at least 2 and not more than 8000. The value of w will be at most 30. The value of d will

be less than w.

Output

For each instance of the problem, your program will produce one line of output, consisting of one

positive integer: the number of the basket that contains lighter coins than the other baskets.

Sample Input

10 25 8 1109

10 25 8 1045

8000 30 12 959879400

Sample Output

2

10

50

#include <iostream>

int main(int argc, const char* argv[])
{
int n = 0, w = 0, d = 0, result = 0;
while (std::cin >> n >> w >> d >> result)
{
int nTemp = (((n-1)*n/2)*w - result)/d;
if (nTemp == 0)
{
std::cout << n << std::endl;
}
else
{
std::cout << nTemp << std::endl;
}
}

return 0;
}