#include <bits/stdc++.h>

#define inc(i,a,b) for(register int i=a;i<=b;i++)

#define dec(i,a,b) for(register int i=a;i>=b;i--)

using namespace std;

int head[2000010],cnt;

class littlestar{

	public:

		int to;

		int nxt;

}star[2000010];

void add(int u,int v){

	star[++cnt].to=v;

	star[cnt].nxt=head[u];

	head[u]=cnt;

}

int n,m;

template<class nT>

inline void read(nT& x)

{

	char c;

	while(c=getchar(),!isdigit(c));

	x=c^48;

	while(c=getchar(),isdigit(c)) x=x*10+c-48;

}

int a[2000010],val[2000010];

int dep[2000010],f[1000010][30];

void pre(int u,int fa)

{

	//printf("%d %d\n",u,fa);

	dep[u]=dep[fa]+1;

	inc(i,0,20){

		f[u][i+1]=f[f[u][i]][i];

	}

	for(register int i=head[u];i;i=star[i].nxt){

		int v=star[i].to;

		if(v==fa) continue;

		f[v][0]=u;

		pre(v,u);

	}

}

int lca(int x,int y)

{

	if(dep[x]<dep[y]) swap(x,y);

	dec(i,19,0){

		if(dep[f[x][i]]>=dep[y]) x=f[x][i];

		if(x==y) return x;

	}

	dec(i,19,0){

		if(f[x][i]!=f[y][i]){

			x=f[x][i];

			y=f[y][i];

		}

	}

	return f[x][0];

}

int rt[20000010];

int num=0;

class node2{

	public:

 		int l;

 		int r;

 		int w;

}tree[20000010];

void insert(int preroot,int &root,int l,int r,int goal){

	tree[root=++num]=tree[preroot];

	tree[root].w++;

	if(l==r) return;

	int mid=(l+r)>>1;

	if(goal<=mid){

		insert(tree[preroot].l,tree[root].l,l,mid,goal);

	}

	else{

		insert(tree[preroot].r,tree[root].r,mid+1,r,goal);

	}

	tree[root].w=(tree[tree[root].l].w+tree[tree[root].r].w);

}

int query(int l,int r,int x,int y,int lc,int falc,int k){

	if(l==r) return l;

	int tmp=tree[tree[x].l].w+tree[tree[y].l].w-tree[tree[lc].l].w-tree[tree[falc].l].w;

	int mid=(l+r)>>1;

	if(k<=tmp){

		return query(l,mid,tree[x].l,tree[y].l,tree[lc].l,tree[falc].l,k);

	}

	else{

		return query(mid+1,r,tree[x].r,tree[y].r,tree[lc].r,tree[falc].r,k-tmp);

	}

}

void dfs(int u)

{

	insert(rt[f[u][0]],rt[u],1,n,val[u]);

	for(register int i=head[u];i;i=star[i].nxt){

		int v=star[i].to;

		if(v==f[u][0]) continue;

		dfs(v);

	}

}

int ago[2000010];

signed main()

{

	//freopen("ha.in","r",stdin);

	read(n); read(m);

	inc(i,1,n) read(a[i]),val[i]=a[i];

	inc(i,1,n-1){

		int u,v;

		read(u); read(v);

		add(u,v);

		add(v,u);

	}

	sort(a+1,a+1+n);

	int lisan=unique(a+1,a+1+n)-a-1;

	inc(i,1,n){

		int tmp=val[i];

		val[i]=lower_bound(a+1,a+1+lisan,val[i])-a;

		ago[val[i]]=tmp;

	}

	pre(1,0);

	dfs(1);

	int onlineans=0;

	inc(i,1,m){

		int u,v,k;

		read(u);read(v);read(k);

		u^=onlineans;

		int LCA=lca(u,v);

		int last=query(1,n,rt[u],rt[v],rt[LCA],rt[f[LCA][0]],k);

		onlineans=ago[last];

		printf("%d\n",onlineans);

	}

}