Cod sursă (job #442032)

#include <bits/stdc++.h>

using namespace std;

ifstream fin("scv.in");
ofstream fout("scv.out");

int main()
{
    long long c,t,m,x;
    fin >> c >> t >> m >> x;
    int sum=0;
    int scv=1;
    long long rasp=0;
    while(sum<x)
    {
        while(sum<c and sum<x)
        {
            rasp++;
            sum+=scv*m;
        }
        if(m*scv*t+m*scv*(c/m)+sum<x)
        {
            sum+=m*scv*t-c;
            rasp+=t;
            scv++;
        }
        else
        {
            rasp+=(x-sum)/(scv*m);
            sum=x+1;
        }
    }
    fout << rasp;
    return 0;
}