Cod sursă (job #442693)

#include<cstdio>
using namespace std;

int main(){
    freopen("scv.in","r",stdin);
    freopen("scv.out","w",stdout);
    int c,t,m,x;
    scanf("%d%d%d%d", &c, &t, &m, &x);
    int curr=0,sol=0,ad=m;
    while(curr<x){
        while(curr<x && curr<c){
            curr+=ad;
            sol++;
        }
        if(curr+(c/m)*ad+t*ad<x){
            ad+=m;
            sol+=t;
            curr+=t*(ad-m)-c;
        }
        else{
            while(curr<x){
                curr+=ad;
                sol++;
            }
        }
    }
    printf("%d", sol);
    return 0;
}