#include<stdio.h>

 #include<string.h>

 #include<algorithm>

 #include<stdlib.h>

 //#include<iostream>

 using namespace std;

 int n,m;

 #define maxn 100011

 #define maxm 2000011

 struct SMT

 {

     struct Node

     {

         int son[];

         int cnt;

     }a[maxm];

     int size,n;

     void clear(int m) {n=m;size=;a[].cnt=;}

     void build(int pre,int &rt,int L,int R,int num)

     {

         rt=++size;

         a[rt].cnt=a[pre].cnt+;

         if (L==R) {a[rt].son[]=a[rt].son[]=;return;}

         const int mid=(L+R)>>;

         if (num<=mid) build(a[pre].son[],a[rt].son[],L,mid,num),a[rt].son[]=a[pre].son[];

         else build(a[pre].son[],a[rt].son[],mid+,R,num),a[rt].son[]=a[pre].son[];

     }

     void build(int pre,int &rt,int num) {build(pre,rt,,n,num);}

 //    void test(int x,int L,int R)

 //    {

 //        const int mid=(L+R)>>1;

 //        if (a[x].son[0]) test(a[x].son[0],L,mid);

 ////        cout<<L<<' '<<R<<' '<<a[x].cnt<<endl;

 //        if (a[x].son[1]) test(a[x].son[1],mid+1,R);

 //    }

 //    void test(int x) {test(x,1,n);}

 }smt;

 struct Edge{int to,next;}edge[maxn<<];int first[maxn],le=;

 void in(int x,int y) {Edge &e=edge[le];e.to=y;e.next=first[x];first[x]=le++;}

 void insert(int x,int y) {in(x,y);in(y,x);}

 int a[maxn],b[maxn],lb;

 int fa[maxn][],dep[maxn],rt[maxn];

 void dfs(int x,int f)

 {

     fa[x][]=f;dep[x]=dep[f]+;

     for (int j=;j<=;j++)

         fa[x][j]=fa[fa[x][j-]][j-];

     smt.build(rt[f],rt[x],a[x]);

     for (int i=first[x];i;i=edge[i].next)

     {

         const Edge &e=edge[i];if (e.to==f) continue;

         dfs(e.to,x);

     }

 }

 void pre() {dfs(,);}

 int lca(int x,int y)

 {

     if (dep[x]<dep[y]) {int t=x;x=y;y=t;}

     for (int i=;i>=;i--) if (dep[fa[x][i]]>=dep[y]) x=fa[x][i];

     if (x==y) return x;

     for (int i=;i>=;i--) if (fa[x][i]!=fa[y][i]) x=fa[x][i],y=fa[y][i];

     return fa[x][];

 }

 int main()

 {

     scanf("%d%d",&n,&m);

     for (int i=;i<=n;i++) scanf("%d",&a[i]),b[i]=a[i];

     lb=n;sort(b+,b++lb);lb=unique(b+,b++lb)-b-;

     for (int i=;i<=n;i++) a[i]=lower_bound(b+,b++lb,a[i])-b;

     smt.clear(lb);

     for (int i=,x,y;i<n;i++)

     {

         scanf("%d%d",&x,&y);

         insert(x,y);

     }

     pre();

 //    for (int i=1;i<=n;i++) smt.test(rt[i]),cout<<endl;

     int last=;

     for (int i=,x,y,K;i<=m;i++)

     {

         scanf("%d%d%d",&x,&y,&K);

         x^=last;

         int z=lca(x,y),w=fa[z][],L=,R=lb,tmp;

 //        cout<<x<<' '<<y<<' '<<z<<' '<<w<<endl;

         x=rt[x];y=rt[y];z=rt[z];w=rt[w];

         while (L<R)

         {

             if ((tmp=smt.a[smt.a[x].son[]].cnt+smt.a[smt.a[y].son[]].cnt

             -smt.a[smt.a[z].son[]].cnt-smt.a[smt.a[w].son[]].cnt)>=K)

                 x=smt.a[x].son[],y=smt.a[y].son[],z=smt.a[z].son[],w=smt.a[w].son[],R=(L+R)>>;

             else x=smt.a[x].son[],y=smt.a[y].son[],z=smt.a[z].son[],w=smt.a[w].son[],K-=tmp,L=((L+R)>>)+;

 //            cout<<tmp<<' '<<K<<endl;

         }

         printf("%d",(last=b[L]));

         if (i<m) puts("");

     }

     return ;

 }