Cod sursă (job #819713)

#include<bits/stdc++.h>
#pragma GCC optimize("Ofast,unroll-loops,inline")
#define fast ios_base::sync_with_stdio(0);f.tie(0);g.tie(0);
using namespace std;
const string file="scv";
ifstream f(file+".in");
ofstream g(file+".out");
//#define f cin
//#define g cout
int c,t,m,x,stoc,zile,scv,r;
int zilemin=INT_MAX;
bool ok;
int bulan(int mij){
    zile=0,stoc=0,scv=1;
    while(stoc<x){
        if(stoc>=c && scv<mij){
            stoc-=c;
            int z=t;
            while(z>0){
                stoc+=scv*m;
                --z;
                ++zile;
                if(stoc>=x) break;
            }
            ++scv;
        }
        else stoc+=scv*m,zile++;
    }
    return zile;
}
int main(){ fast
    f>>c>>t>>m>>x;
    for(int i=1; i<=x/t+m; ++i){
        int z=bulan(i);
        if(z<zilemin) zilemin=z;
        else break;
    }

    g<<zilemin;
    return 0;
}