一堆WA：我的作答

有没有大佬帮忙修改一下啊

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll SIZE=120000;
ll rest[SIZE],a[SIZE];
int main(){
	ll n,m,ans=0,oil=0,money=0x7fffffff,road;
	scanf("%lld%lld",&n,&m);
	for (int i=1;i<n;i++) scanf("%lld",&a[i]);
	for (int i=1;i<=n;i++) scanf("%lld",&rest[i]);
	for (int i=1;i<n;i++){
		if (rest[i]<=money) money=rest[i];
		road=a[i]-oil,oil=road%m,road/=m;
		if (oil) road++;
		ans+=money*road;
	}
	printf("%lld",ans);
	return 0;
}