#include<bits/stdc++.h>
using namespace std;
namespace my_std{
#define mems(x,y) memset(x,y,sizeof x)
#define Mp make_pair
#define eb emplace_back
#define gc getchar
#define pc putchar
#define fi first
#define se second
#define il inline
#define rep(i,a,b) for(int i=(a);i<=(b);i++)
#define drep(i,a,b) for(int i=(a);i>=(b);i--)
#define go(i,u) for(int i=head[u];i;i=e[i].nxt)
	typedef long long ll;
	typedef pair<int,int> pii;
	template<typename T>
	il void read(T &x){
		int f=1;x=0;char c=gc();
		while(c<'0'||c>'9'){
			if(c=='-'){
				f=-1;
			}
			c=gc();
		}
		while(c>='0'&&c<='9'){
			x=x*10+c-48,c=gc();
		}
		x*=f;
	}
	template<typename T,typename ...Args>
	void read(T &x,Args &...args){
		read(x),read(args...);
	}
	template<typename T>
	il void write(T x){
		char buf[43];int len=0;
		if(x<0){
			pc('-'),x=-x;
		}
		do{
			buf[++len]=x%10,x/=10;
		}while(x);
		while(len){
			pc(buf[len--]+'0');
		}
	}
}
using namespace my_std;
const int N=2e5+7,M=-1,inf=0x3f3f3f3f,mod=0;
int n,m,q,cnt,fa[N],dep[N],ls[N],rs[N];
bool vis[N];
ll s[N],a[N];
multiset<pair<ll,ll>> st;
il void insert(int x,int y){
	auto it=st.emplace(x,y);
	if(it!=st.begin()&&it!=--st.end()&&prev(it)->se>next(it)->fi){
		cnt--;
	}
	if(it!=st.begin()&&prev(it)->se>x){
		cnt++;
	}
	if(it!=--st.end()&&y>next(it)->fi){
		cnt++;
	}
}
il void erase(int x,int y){
	auto it=st.erase(st.find(Mp(x,y)));
	if(it!=st.begin()&&it!=st.end()&&prev(it)->se>it->fi){
		cnt++;
	}
	if(it!=st.begin()&&prev(it)->se>x){
		cnt--;
	}
	if(it!=st.end()&&y>it->fi){
		cnt--;
	}
}
void dfs(int u,int f){
	fa[u]=f,dep[u]=dep[f]+1;
	if(dep[u]>80){
		while(q--){
			puts("NO");
		}
		exit(0);
	}
	if(u<=n){
		s[u]=a[u];
		return;
	}
	dfs(ls[u],u),dfs(rs[u],u);
	s[u]+=s[ls[u]]+s[rs[u]];
	ll x=s[ls[u]],y=s[rs[u]];
	if(x>y){
		swap(x,y);
	}
	insert(x,y);
}
void Yorushika(){
	read(n,q);
	rep(i,1,n){
		read(a[i]);
	}
	rep(i,n+1,n+n-1){
		read(ls[i],rs[i]);
		vis[ls[i]]=vis[rs[i]]=1;
	}
	int rt=0;
	rep(i,n+1,n+n-1){
		if(!vis[i]){
			rt=i;	
		}
	}
	dfs(rt,0);
	puts(cnt?"NO":"YES");
	q--;
	while(q--){
		ll x,y;read(x,y);
		int u=x;
		while(u){
			// printf("**%d %d %d\n",u,ls[fa[u]],rs[fa[u]]);
			if(u==ls[fa[u]]){
				ll l=s[u],r=s[rs[fa[u]]];
				bool fl=0;
				if(l>r){
					swap(l,r),fl^=1;
				}
				erase(l,r);
				if(fl){
					r+=y-a[x];
				}else{
					l+=y-a[x];
				}
				if(l>r){
					swap(l,r);
				}
				insert(l,r);
			}else if(u==rs[fa[u]]){
				ll l=s[u],r=s[ls[fa[u]]];
				bool fl=0;
				if(l>r){
					swap(l,r),fl^=1;
				}
				erase(l,r);
				if(fl){
					r+=y-a[x];
				}else{
					l+=y-a[x];
				}
				if(l>r){
					swap(l,r);
				}
				insert(l,r);
			}
			s[u]+=y-a[x];
			u=fa[u];
		}
		a[x]=y;
		puts(cnt?"NO":"YES");
	}
}
signed main(){
	int t=1;
	//read(t);
	while(t--){
		Yorushika();
	}
}