Cod sursă (job #108360)

#include <cstdio>

using namespace std;

int main()
{
    FILE *fin,*fout;
    fin=fopen("scv.in","r");
    fout=fopen("scv.out","w");
    int c,t,m,x,s=0,nr=1,cnt=0,k;
    fscanf(fin,"%d%d%d%d",&c,&t,&m,&x);
    while(s<x)
    {
      s+=nr*m;
      if(s>=c)
      {
          k=nr*m*t;
       if((x-s)/(nr*m)>(x-k-s+c)/((nr+1)*m)+t)
       {
           nr++;
           s=s-c+(nr-1)*m*t;
           cnt+=t;


       }
      }
      cnt++;
    }
    fprintf(fout,"%d",cnt);
        return 0;
}