#include<bits/stdc++.h>
// #pragma GCC optimize("Ofast","inline","-ffast-math")
// #pragma GCC target("avx,sse2,sse3,sse4,mmx")
using namespace std;
const int N=1e5+5,M=80;
int n,q,mxdep,fa[N<<1],dep[N<<1],ls[N<<1],rs[N<<1];
long long val[N<<1],a[N];
multiset<pair<long long,long long>> s;
multiset<long long> sd[M+5];
int cnt;
inline bool check(pair<long long,long long> x,pair<long long,long long> y){
	return (y.second<x.first);
}
inline int cp(int x){
	return (ls[fa[x]]==x?rs[fa[x]]:ls[fa[x]]);
}
inline pair<long long,long long> get(int p){
	return {val[p],val[cp(p)]};
}
inline void erase(pair<long long,long long> x){
	if(x.first<=x.second)	return;
	auto it=s.find(x);
	if(s.size()!=1){
		if(x==*s.begin())	cnt-=check(x,*++s.begin());
		else if(x==*s.rbegin())	cnt-=check(*--s.rbegin(),x);
		else{
			pair<long long,long long> l=*(--it);it++;
			pair<long long,long long> r=*(++it);it--;
			cnt-=check(l,x)+check(x,r)-check(l,r);
		}
	}
	s.erase(it);
}
inline void insert(pair<long long,long long> x){
	if(x.first<=x.second)	return;
	auto it=s.insert(x);
	if(s.size()!=1){
		if(x==*s.begin())	cnt+=check(x,*++s.begin());
		else if(x==*s.rbegin())	cnt+=check(*--s.rbegin(),x);
		else{
			pair<long long,long long> l=*(--it);it++;
			pair<long long,long long> r=*(++it);
			cnt+=check(l,x)+check(x,r)-check(l,r);
		}
	}
}
inline void changeval(int p,long long v){
	sd[dep[p]].erase(sd[dep[p]].find(val[p])),sd[dep[p]].insert(v);
	if(dep[p]==1){val[p]=v;return;}
	pair<long long,long long> e1=get(p),e2=get(cp(p));
	val[p]=v;
	pair<long long,long long> i1=get(p),i2=get(cp(p));
	erase(e1),erase(e2),insert(i1),insert(i2);
}
inline void change(int p,long long v){
	changeval(p,v);
	while(p!=n*2-1)	p=fa[p],changeval(p,val[ls[p]]+val[rs[p]]);
}
inline bool solve(){
	for(int i=1;i<mxdep;i++) if(*sd[i].begin()<*(--sd[i+1].end()))	return 0;
	return cnt==0;
}
int main(){
	// freopen("ex_huffman4.in","r",stdin);
	// freopen("ex_huffman4.my","w",stdout);
	ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
	cin>>n>>q;
	if(n==1){
		while(q--)	puts("YES");
		return 0;
	}
	for(int i=1;i<=n;i++)	cin>>a[i],val[i]=a[i];
	for(int i=n+1;i<n*2;i++){
		cin>>ls[i]>>rs[i];
		fa[ls[i]]=i,fa[rs[i]]=i,val[i]=val[ls[i]]+val[rs[i]];
	}
	dep[n*2-1]=1;
	mxdep=1;
	for(int i=n*2-1;i>=n+1;i--){
		dep[ls[i]]=dep[i]+1,dep[rs[i]]=dep[i]+1;
		mxdep=max(mxdep,dep[ls[i]]),mxdep=max(mxdep,dep[rs[i]]);
	}
	if(mxdep>M){
		while(q--)	puts("NO");
		return 0;
	}
	for(int i=1;i<=n*2-1;i++)	sd[dep[i]].insert(val[i]);
	for(int i=1;i<=n*2-2;i++)	insert(get(i));
	puts(solve()?"YES":"NO");
	q--;
	while(q--){
		int p;
		long long v;
		cin>>p>>v;
		change(p,v);
		puts(solve()?"YES":"NO");
	}
	return 0;
}