#include <iostream>
#include <algorithm>
#include <vector>
#include <cstring>
#include <queue>
using namespace std;
#define maxn 200001
#define int long long
struct edge{
	int v,w;
};
struct node{
	int dis,u;
	bool operator > (const node &a)const{
		return dis > a.dis;
	}
};
vector<edge> e[maxn];
int dis[maxn],vis[maxn],sc[maxn];
priority_queue<node,vector<node>,greater<node> > q;
void dijkstra(int s){
	dis[s]=0;
	q.push({0,s});
	while(!q.empty()){
		int u=q.top().u;
		q.pop();
		if(vis[u])continue;
		vis[u]=1;
		for(int i=0;i<e[u].size();i++){
			edge ed=e[u][i];
			int v=ed.v,w=ed.w;
			if(dis[v]>dis[u]+w){
				dis[v]=dis[u]+w;
				q.push({dis[v],v});
			}
		}
	}
}
int n,Q,k;
signed main(){
	cin>>n>>Q>>k;
	for(int i=1;i<=n;i++){
		cin>>sc[i];
	}
	for(int i=1,x,y;i<n;i++){
		cin>>x>>y;
		e[x].push_back({y,sc[y]});
		e[y].push_back({x,sc[x]});
	}
	while(Q--){
		int x,y;
		cin>>x>>y;
		memset(vis,0,sizeof(vis));
		memset(dis,0x3f,sizeof(dis));
		dijkstra(x);
		cout<<dis[y]<<'\n';
	}
	return 0;
}

我没看错吧，这就是求最短路啊，我就想用Dij求一下看看答案，怎么就不对了呢？？？难道只能用LCA，我们忽略超时的情况，就说Dijkstra能不能解吧，肯定能解的呀，怎么输出是错的呢？？？