CF533A Berland Miners

线段树维护贪心
/*


*/
#include<cstdio>
#include<algorithm>
#include<cstring>
#include<iostream>
#include<queue>
#include<cmath>
#include<set>
#define ll long long
#define M 500010
#define mmp make_pair
#define INF 1000000000
using namespace std;
int read() {
	int nm = 0,  f = 1;
	char c = getchar();
	for(; !isdigit(c); c = getchar()) if(c == '-') f = -1;
	for(; isdigit(c); c = getchar()) nm = nm * 10 + c - '0';
	return nm * f;
}
vector<int> v[M] ;
int h[M], hm[M], st_tmp[M], scnt ;
struct P {
	int id, hm ;
	bool operator < (const P &rhs) const {
		return hm<rhs.hm ;
	}
} cave[M];

void dfs0(int x, int f, int nowh) {
	hm[x]=nowh ;
	for(auto i : v[x]) if(i != f)
			dfs0(i, x, min(nowh, h[i])) ;
}
int tmp[M], tcnt ;
void dfs2(int x, int f, int nowhm) {
	tmp[tcnt++]=nowhm ;
	for(auto i : v[x]) if(i != f) {
			int newhm=min(nowhm, h[i]) ;
			if(newhm > hm[i]) dfs2(i, x, newhm) ;
		}
}

multiset<int> st ;
bool check() {
	if(tcnt < st.size()) return 0 ;
	scnt=0 ;
	for(int i=0; !st.empty() && i<tcnt; i++) {
		auto it=st.upper_bound(tmp[i]) ;
		if(it != st.begin())
			it-- ,  st_tmp[scnt++]=*it ,  st.erase(it) ;
	}
	int sz=st.size() ;
	for(int i=0; i<scnt; i++) st.insert(st_tmp[i]) ;
	return sz==0 ;
}

int LIM ;
bool dfs(int x, int f, int add) {
	if(h[x]<=LIM) {
		int newhm= (f==-1 ? h[x]+add : min(hm[f], h[x]+add)) ;
		if(newhm>hm[x]) {
			tcnt=0 ;
			dfs2(x, f, newhm) ;
			if(check()) return 1 ;
		}
	}
	for(auto i : v[x]) if(i != f && dfs(i, x, add))
			return 1 ;
	return 0 ;
}

main() {
	int n = read();
	for(int i=1; i<=n; i++) h[i] = read();
	for(int i=1; i<n; i++) {
		int x = read(), y = read();
		v[x].push_back(y) ;
		v[y].push_back(x) ;
	}
	dfs0(1, -1, h[1]) ;

	int k = read();
	for(int i=1, x; i<=k; i++) x = read(),  st.insert(x) ;
	for(int i=k+1; i<=n; i++) st.insert(0) ;
	for(int i=1; i<=n; i++) cave[i]=(P) {
		i, hm[i]
	} ;
	sort(cave+1, cave+n+1) ;

	LIM=-1 ;
	for(int i=1; i<=n; i++) {
		auto it=st.upper_bound(cave[i].hm) ;
		if(it != st.begin()) st.erase(--it) ;
		else if(LIM==-1) LIM=cave[i].hm ;
	}
	if(st.empty()) {
		printf("0\n") ;
		return 0;
	}
	if(!dfs(1, -1, INF)) {
		printf("-1\n") ;
		return 0 ;
	}

	int l=0 ,  r=INF ;
	while(r-l>1) {
		int mid=(r+l)/2 ;
		if(dfs(1, -1, mid)) r=mid ;
		else l=mid ;
	}
	printf("%d\n", r) ;
}