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#include <bits/stdc++.h>
#include <bits/extc++.h>
#define mp make_pair
#define rep(x,y,z) for (int x=(y);(x)<=(z);(x)++)
#define per(x,y,z) for (int x=(y);(x)>=(z);(x)--)
#define lowbit(x) ((x)&(-(x)))
#ifdef DEBUG
#define debugdo(X) X
#define debugndo(X)
#define debugout(X) cout<<(#X)<<"="<<(X)<<endl
#else
#define debugdo(X)
#define debugndo(X) X
#define debugout(X)
#endif
const int inf=0x3f3f3f3f;
using namespace std;
typedef long long LL;
typedef pair<int,int> pairs;
template<typename T>
inline void read(T &x){char ch;x=0;bool flag=false;ch=getchar();while (ch>'9'||ch<'0') {if (ch=='-') flag=true;ch=getchar();}while ((ch<='9'&&ch>='0')){x=x*10+ch-'0';ch=getchar();}if (flag) x*=-1;}
template<typename T,typename U>
inline void read(T &x,U &y){read(x);read(y);}
template<typename T,typename U,typename V>
inline void read(T &x,U &y,V &z){read(x);read(y);read(z);}
const int maxn=111111,maxvalue=100000;
int n,m,a[maxn];
map<int,int> ma;
struct node
{
node *l,*r;
int value;
node():l(0),r(0),value(0){}
node(node *ll,node *rr):l(ll),r(rr),value((ll?ll->value:0)+(rr?rr->value:0)){}
node(int vv):l(0),r(0),value(vv){}
};
node *root[maxn];
char memorypool[maxn*sizeof(node)*60];//1 char=1 byte
char *memorypoolptr=memorypool;
inline void* myalloc(size_t size)
{
return (memorypoolptr+=size)-size;
}
#define newnode new (myalloc(sizeof(node))) node
node* insert(node *x,int k,int L=0,int R=maxvalue)
{
if (L==R) return newnode(x?x->value+1:1);
int mid=(L+R)>>1;
if (k<=mid) return newnode(insert(x?x->l:0,k,L,mid),x?x->r:0);
else return newnode(x?x->l:0,insert(x?x->r:0,k,mid+1,R));
}
int kth(node *x,int k,int L=0,int R=maxvalue)
{
if (L==R) return L;
int mid=(L+R)>>1;
if (k<=(x->l?x->l->value:0)) return kth(x->l,k,L,mid);
else return kth(x->r,k-(x->l?x->l->value:0),mid+1,R);
}
int kth(node *x,node *y,int k,int L=0,int R=maxvalue)
{
if (L==R) return L;
if (!x) return kth(y,k,L,R);
int mid=(L+R)>>1,temp=(y->l?y->l->value:0)-(x->l?x->l->value:0);
if (k<=temp) return kth(x->l,y->l,k,L,mid);
else return kth(x->r,y->r,k-temp,mid+1,R);
}
int kth(node *x1,node *x2,node *y1,node *y2,int k,int L=0,int R=maxvalue)
{
if (L==R) return L;
int mid=(L+R)>>1,temp=(y1?(y1->l?y1->l->value:0):0)+(y2?(y2->l?y2->l->value:0):0)-(x1?(x1->l?x1->l->value:0):0)-(x2?(x2->l?x2->l->value:0):0);
if (k<=temp) return kth(x1?x1->l:0,x2?x2->l:0,y1?y1->l:0,y2?y2->l:0,k,L,mid);
else return kth(x1?x1->r:0,x2?x2->r:0,y1?y1->r:0,y2?y2->r:0,k-temp,mid+1,R);
}
struct GRAPH
{
int nxt[maxn<<1],first[maxn],to[maxn<<1],cnt;
int depth[maxn],f[maxn][30];
void addedge(int x,int y)
{
nxt[++cnt]=first[x];
first[x]=cnt;
to[cnt]=y;
}
void addedge2(int x,int y){addedge(x,y);addedge(y,x);}
void dfs(int x,int fa)
{
depth[x]=depth[fa]+1;
for (int i=1;(1<<i)<=depth[x];i++) f[x][i]=f[f[x][i-1]][i-1];
root[x]=insert(root[fa],a[x]);
for (int q=first[x];q;q=nxt[q]) if (to[q]!=fa) {f[to[q]][0]=x;dfs(to[q],x);}
}
int lca(int x,int y)
{
if (depth[x]<depth[y]) swap(x,y);
per(i,25,0)
{
if (depth[f[x][i]]>=depth[y]) x=f[x][i];
if (x==y) return x;
}
per(i,25,0) if (f[x][i]!=f[y][i]){x=f[x][i];y=f[y][i];}
return f[x][0];
}
}g;
int b[maxn];
int main()
{
read(n,m);
rep(i,1,n) read(a[i]);
rep(i,1,n) b[i]=a[i];
sort(b+1,b+n+1);
int nn=unique(b+1,b+n+1)-b;
rep(i,1,nn) ma[b[i]]=i;
rep(i,1,n) a[i]=ma[a[i]];
int x,y;
rep(i,1,n-1) {read(x,y);g.addedge2(x,y);}
g.dfs(1,0);
int lastans=0;
rep(i,1,m)
{
int u,v,k;
read(u,v,k);
u^=lastans;
int lca=g.lca(u,v);
int ans=b[kth(root[lca],root[g.f[lca][0]],root[u],root[v],k)];
printf("%d\n",lastans=ans);
}
return 0;
}
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