咕，基本就是看了题解然后打出来的

改了比较久，但是RE，WA很多

（因为找不出错误改的尽量和题解一样

（但还是错的

Code：

#include<bits/stdc++.h>
using namespace std;
long long son[1000005],len[1000005],nxt[1000005],fir[1000005],ned[1000005],army[1000005],n,m,r=0,deep[1000005],num[1000005][20],ending[1000005],dis[1000005][20],oto=0,tot=0,oot=0,spe=0,ans;
struct data{long long last,p;}fre[1000005];
bool stay[1000005],need[1000005],f=false;
bool cmp(data a,data b){return a.last<b.last;}
long long read(){
	long long sum=0,e=1;char c=getchar();
	while(!(c>='0'&&c<='9')){if(c=='-')e=-1;c=getchar();}
	while(c>='0'&&c<='9'){sum=sum*10+c-'0';c=getchar();}
	return sum*e;
}
void add(long long x,long long y,long long z){son[++r]=y;len[r]=z;nxt[r]=fir[x];fir[x]=r;}
void dfson(long long x){
	for(long long i=fir[x];i;i=nxt[i]){
	    if(deep[son[i]])continue;
	    deep[son[i]]=deep[x]+1;
	    num[son[i]][0]=x,dis[son[i]][0]=len[i];
	    for(long long j=1;j<=log2(n)+1;j++){
	    	num[son[i]][j]=num[num[son[i]][j-1]][j-1];
			dis[son[i]][j]=dis[son[i]][j-1]+dis[num[son[i]][j-1]][j-1];
		}
		dfson(son[i]);
	}
}
bool dfs(long long x){
	if(stay[x])return true;
    bool flag=false;
	for(long long i=fir[x];i;i=nxt[i]){
		if(deep[son[i]]<deep[x])continue;
		flag=true;
		if(!dfs(son[i]))return false;
	}
	if(!flag)return false;
	return true;
}
bool check(long long timline){
	memset(stay,false,sizeof(stay));
	memset(need,false,sizeof(need));
	for(long long i=1;i<=tot;i++)fre[i].last=fre[i].p=0;
	memset(ned,0,oot+1);
	memset(ending,0,oto+1);
	tot=oto=oot=0;
	for(long long i=1;i<=m;i++){
		long long x=army[i],sum=0;
		for(long long j=log2(n)+1;j>=0;j--){
			if(num[x][j]>1&&sum+dis[x][j]<=timline)sum+=dis[x][j],x=num[x][j];
            if(num[x][0]==1&&sum+dis[x][0]<=timline)fre[++tot].last=timline-sum-dis[x][0],fre[tot].p=x;
            else stay[x]=true;
		}
	}
	for(long long i=fir[1];i;i=nxt[i])if(!dfs(son[i]))need[son[i]]=true;
	sort(fre+1,fre+tot+1,cmp);
	for(long long i=1;i<=tot;i++)
		if(need[fre[i].p]&&fre[i].last<dis[fre[i].last][0])need[fre[i].p]=false;
		else ending[++oto]=fre[i].last;
    for(long long i=fir[1];i;i=nxt[i])if(need[son[i]])ned[++oot]=dis[son[i]][0];
	if(oot>oto)return false;
    sort(ending+1,ending+oto+1);sort(ned+1,ned+oot+1);
    long long qe=1,qn=1;
    while(qe<=oto&&qn<=oot)
    	if(ending[qe]>=ned[qn])qe++,qn++;
    	else qe++;
    if(qn>oot)return true;
	return false;
}
void find(){
	long long L=1,R=spe,M;
	while(L<=R){
		M=(L+R)/2;
		if(check(M))R=M-1,ans=M,f=true;
		else L=M+1;
	}
}
int main(){
	n=read();
	for(long long i=1;i<n;i++){
		long long a=read(),b=read(),c=read();
		add(a,b,c);add(b,a,c);spe+=c;
	}
	m=read();
	for(long long i=1;i<=m;i++)army[i]=read();
//	bfs();
	deep[1]=1;
	dfson(1);find();
    if(!f)cout<<-1;
    else cout<<ans;
	return 0;
}