#include<bits/stdc++.h>
using namespace std;
const int N=100005;
int n,m,in[N],ls[N],tot,w[N],siz[N],top[N],de[N],f[N],rt[N],len,la;
int to[2*N],ne[2*N],fi[2*N],idx; 
struct tree{
	int lc,rc,val;
}t[30*N];
void link(int x,int y){
	to[++idx]=y;ne[idx]=fi[x];fi[x]=idx;
}
void build(int &x,int l,int r){
	x = ++tot;
	if(l==r) return ;
	int mid=(l+r)>>1;
	build(t[x].lc,l,mid);
	build(t[x].rc,mid+1,r);
}
void insert(int &x,int last,int l,int r,int pos){
	x = ++tot;
	t[x] = t[last];
	t[x].val++;
	if(l==r) return ;
	int mid=(l+r)>>1;
	if(pos<=mid) insert(t[x].lc,t[last].lc,l,mid,pos);
	else insert(t[x].rc,t[last].rc,mid+1,r,pos);
}
void debug(int x){
	cout<<t[x].val<<" ";
	if(t[x].lc==t[x].rc) return ;
	if(t[x].lc) debug(t[x].lc);
	if(t[x].rc) debug(t[x].rc);
}
void dfs1(int x,int fa){
	siz[x]=1;de[x]=de[fa]+1; f[x]=fa;
	int pos = lower_bound(ls+1,ls+len+1,in[x])-ls;
	insert(rt[x],rt[fa],1,len,pos);
	for(int i=fi[x];i;i=ne[i]) if(to[i]!=fa){
		dfs1(to[i],x);
		siz[x]+=siz[to[i]];
		if(siz[to[i]]>siz[w[x]]) w[x]=to[i];
	}
}
void dfs2(int x,int Top){
	top[x]=Top;
	if(w[x]) dfs2(w[x],Top);
	for(int i=fi[x];i;i=ne[i]) if(to[i]!=f[x] && to[i]!=w[x]){
		dfs2(to[i],to[i]);
	}
}
int LCA(int x,int y){
	while(top[x]!=top[y]){
		if(de[top[x]]<de[top[y]]) swap(x,y);
		x = f[top[x]];
	}
	return de[x]<de[y] ? x:y;
}
int query(int x,int y,int z,int v,int l,int r,int pos){
	if(l==r) return l;
	int cnt = t[t[x].lc].val+t[t[y].lc].val-t[t[z].lc].val-t[t[v].lc].val;
	int mid=(l+r)>>1;
	if(cnt>=pos) query(t[x].lc,t[y].lc,t[z].lc,t[v].lc,l,mid,pos);
	else query(t[x].rc,t[y].rc,t[z].rc,t[v].rc,mid+1,r,pos-cnt);
}
int main(){
	scanf("%d%d",&n,&m);
	for(int i=1;i<=n;i++) scanf("%d",&in[i]),ls[i]=in[i];
	sort(ls+1,ls+n+1);
	len = unique(ls+1,ls+n+1)-ls-1;
	for(int i=1,x,y;i<=n-1;i++){
		scanf("%d%d",&x,&y);
		link(x,y);link(y,x);
	}
	build(rt[0],1,len);
	dfs1(1,0);
	dfs2(1,1);
	int x,y,k;
	while(m--){
		scanf("%d%d%d",&x,&y,&k);
		x ^= la;
		int lca=LCA(x,y);
		la = ls[query(rt[x],rt[y],rt[lca],rt[f[lca]],1,len,k)];
		printf("%d\n",la); 
	}
	return 0;
}