#include<map>
#include<set>
#include<cmath>
#include<ctime>
#include<queue>
#include<stack>
#include<cstdio>
#include<vector>
#include<string>
#include<bitset>
#include<numeric>
#include<cstring>
#include<cstdlib>
#include<iostream>
#include<algorithm>
using namespace std;
const int MAXN=1e5+10;
const int N=1e5;
const int INF=0x3f3f3f3f;
const long long LINF=0x3f3f3f3f3f3f3f3f;
const int mod=1e9+7;
int n,q;
long long a[MAXN<<1];
int f[MAXN<<1];
int ls[MAXN<<1],rs[MAXN<<1];
#define pii pair<long long,long long>
multiset <pii> s;
long long cnt=0;
#define calc(x,y) ((y).first<(x).second)
inline void add(pii x){
	auto it=s.insert(x);
	if(it!=s.begin()){
		cnt+=calc(*prev(it),x);
	}
	if(next(it)!=s.end()){
		cnt+=calc(x,*next(it));
	}
	if(it!=s.begin()&&next(it)!=s.end()){
		cnt-=calc(*prev(it),*next(it));
	}
}
inline void del(pii x){
	auto it=s.find(x);
	if(it!=s.begin()){
		cnt-=calc(*prev(it),x);
	}
	if(next(it)!=s.end()){
		cnt-=calc(x,*next(it));
	}
	if(it!=s.begin()&&next(it)!=s.end()){
		cnt+=calc(*prev(it),*next(it));
	}
	s.erase(it);
}
inline void mdf(int p,int v){
	for(int x=f[p];x;x=f[x])
	{
		long long l=a[ls[x]],r=a[rs[x]];
		if(l>r){
			swap(l,r);
		}
		del(pii(l,r));
	}
	a[p]=v;
	for(int x=f[p];x;x=f[x])
	{
		long long l=a[ls[x]],r=a[rs[x]];
		a[x]=l+r;
		if(l>r){
			swap(l,r);
		}
		add(pii(l,r));
	}
}
inline void solve(){
	scanf("%d%d",&n,&q);
	for(int i=1;i<=n;i++)
	{
		scanf("%lld",&a[i]);
	}
	for(int i=n+1;i<=n+n-1;i++)
	{
		scanf("%d%d",&ls[i],&rs[i]);
		f[ls[i]]=i;
		f[rs[i]]=i;
	}
	for(int i=n+1;i<=n+n-1;i++)
	{
		long long l=a[ls[i]],r=a[rs[i]];
		a[i]=l+r;
		if(l>r){
			swap(l,r);
		}
		add(pii(l,r));
	}
	puts(!cnt?"YES":"NO");
	while(--q)
	{
		int p,v;
		scanf("%d%d",&p,&v);
		mdf(p,v);
		puts(!cnt?"YES":"NO");
	}
}
signed main(){
	#ifdef LOCAL
	freopen("data.in","r",stdin);
	freopen("data.out","w",stdout);
	atexit([](){fprintf(stderr,"%.3lfs\n",(double)clock()/CLOCKS_PER_SEC);});
	#endif
	solve();
	return 0;
}