RT，我这个贪心都能过就离谱。

//my code
#include<bits/stdc++.h>
using namespace std;
#define N 100005
int n,ans;
vector<int> G[N];
struct node{
	int c,d,id;
}p[N];
bool operator<(node a,node b){
	return a.c==b.c?a.d==b.d?a.id<b.id:a.d<b.d:a.c>b.c;
}
set<node> s;
void push(int u){
	for(auto v:G[u]){
		if(p[v].d==0)continue;
		s.erase(s.find(p[v]));
		p[v].d-=p[u].c;
		if(p[v].d==0)push(v);
		else s.emplace(p[v]);
	}
}
int main(){
	ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
	cin>>n;
	for(int i=1;i<=n;i++)cin>>p[i].d;
	for(int i=1;i<=n;i++)cin>>p[i].c;
	for(int i=1;i<=n;i++)p[i].id=i,s.emplace(p[i]); 
	for(int i=1,x,y;i<n;i++){
		cin>>x>>y;
		G[x].push_back(y);
		G[y].push_back(x);
	}
	while(!s.empty()){
		ans+=s.begin()->d;
		int id=s.begin()->id;
		p[id].d=0;
		s.erase(s.begin());
		push(id);
	} 
	cout<<ans;
	return 0;
}

//hack
#include<bits/stdc++.h>
using namespace std;
#define N 2005
int n;
int d[N],c[N];
mt19937 rnd(time(0));
int main(){
	ios::sync_with_stdio(0),cout.tie(0); 
	cout<<(n=2e3)<<"\n";
	for(int i=1;i<=n;i++)cout<<(d[i]=rnd()%10+1)<<' ';cout<<'\n';
	for(int i=1;i<=n;i++)cout<<(c[i]=rnd()%5+1)<<' ';cout<<'\n';
	for(int i=2;i<=n;i++)cout<<i<<' '<<(rnd()%(i-1)+1)<<'\n'; 
}