Cod sursă (job #560220)

#include <bits/stdc++.h>

using namespace std;

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

int imp(int a, int b){
    if(a%b==0) return a/b;
    return a/b+1;
}

int main()
{
    int s=0,c,t,m,inc,tinta,rez=0;
    in>>c>>t>>m>>tinta;
    inc=m;
    while(s<tinta){
        if(imp(tinta-s,inc)>t+imp(tinta+c-s-inc*t,inc+m) && s>=c){
            s+=inc*t-c;
            inc+=m;
            rez+=t;
        }
        else{
            s+=inc;
            rez++;
        }
    }
    out<<rez;
    return 0;
}