有人能告诉我我哪里错了吗？

#include<bits/stdc++.h>
using namespace std;
#define ll long long
int dyr(){
    ll n,d,money=0,mn=0,sum=0,ok=0;
    cin>>n>>d;
    vector<ll> v(n-1);
    vector<ll> a(n);
    for(auto &it:v) cin>>it;
    for(auto &it:a) cin>>it;
    mn=a[0];
    for(int i=0;i<n;i++){
        sum+=v[i];
        if(ok<sum){
            ll jy=ceil((sum-ok)*1.0/d);
            money+=jy*mn;
            ok+=jy*d;
        }
        ok-=sum;
        sum=0;
        mn=min(mn,a[i+1]);
    }
    cout<<money;
    return 0;
}
int main(){
    freopen("road.in","r",stdin);
    freopen("road.out","w",stdout);
    dyr();
    fclose(stdin);
    fclose(stdout);
}