// MADE BY QT666
#include<cstdio>
#include<algorithm>
#include<cmath>
#include<iostream>
#include<cstring>
#define RG register
using namespace std;
typedef long long ll;
const int N=400050;
int n,m,Q,sz,fa[N],rt[N],ls[N*20],rs[N*20],sum[N*20],hsh[N],Fa[N];
int id[N],dfn[N],ed[N],h[N],v[N],size[N],son[N],top[N];
struct data{
  int a,b,c;
}e[500050];
bool cmp(const data &a,const data &b){return a.c<b.c;}
int head[N],to[N],nxt[N],cnt,tt,tot,res;
inline void lnk(int x,int y){
  to[++cnt]=y,nxt[cnt]=head[x],head[x]=cnt;
}
inline int find(int x){
  if(x!=fa[x]) fa[x]=find(fa[x]);
  return fa[x];
}
inline void dfs1(int x,int f){
  size[x]=1;
  for(RG int i=head[x];i;i=nxt[i]){
    int y=to[i];
    if(y!=f){
      Fa[y]=x;dfs1(y,x);size[x]+=size[y];
      if(size[y]>size[son[x]]) son[x]=y;
    }
  }
}
inline void dfs2(int x,int ff){
  dfn[x]=++tot;id[tot]=x;top[x]=ff;
  if(son[x]) dfs2(son[x],ff);
  for(RG int i=head[x];i;i=nxt[i]){
    int y=to[i];
    if(y!=Fa[x]&&y!=son[x]) dfs2(y,y);
  }
  ed[x]=tot;
}
inline void insert(RG int x,RG int &y,RG int l,RG int r,RG int u){
  y=++sz;ls[y]=ls[x],rs[y]=rs[x];sum[y]=sum[x]+1;
  if(l==r) return;
  RG int mid=(l+r)>>1;
  if(u<=mid) insert(ls[x],ls[y],l,mid,u);
  else insert(rs[x],rs[y],mid+1,r,u);
}
inline int query(RG int x,RG int y,RG int l,RG int r,RG int k){
  if(l==r) return l;
  RG int mid=(l+r)>>1;
  if(sum[ls[y]]-sum[ls[x]]>=k) return query(ls[x],ls[y],l,mid,k);
  else return query(rs[x],rs[y],mid+1,r,k-(sum[ls[y]]-sum[ls[x]]));
}
inline int jump(RG int x,RG int lim){
  RG int j=x;
  while(x&&v[top[x]]<=lim){
    j=top[x],x=Fa[top[x]];
  }
  if(v[x]>lim||v[top[x]]<=lim) return j; 
  RG int l=dfn[top[x]],r=dfn[x],ret=0;
  while(l<=r){
    RG int mid=(l+r)>>1;
    if(v[id[mid]]<=lim) r=mid-1,ret=mid;
    else l=mid+1;
  }
  return id[ret];
}
int main(){
  freopen("Peaks.in","r",stdin);
  freopen("Peaks.out","w",stdout);
  scanf("%d%d%d",&n,&m,&Q);
  for(RG int i=1;i<=n;i++) scanf("%d",&h[i]),hsh[++res]=h[i];
  for(RG int i=1;i<=m;i++) scanf("%d%d%d",&e[i].a,&e[i].b,&e[i].c);
  sort(e+1,e+1+m,cmp);for(int i=1;i<=n;i++) fa[i]=i;tt=n;
  for(RG int i=1;i<=m;i++){
    RG int x=find(e[i].a),y=find(e[i].b);
    if(y!=x){
      tt++;v[tt]=e[i].c;fa[x]=fa[y]=tt;fa[tt]=tt;
      lnk(tt,x);lnk(tt,y);
    }
  }
  for(RG int i=1;i<=tt;i++){
    RG int g=find(i);
    if(!dfn[g]) dfs1(g,g),dfs2(g,g);
  }
  sort(hsh+1,hsh+res+1);res=unique(hsh+1,hsh+1+res)-hsh-1;
  for(RG int i=1;i<=tot;i++){
    rt[i]=rt[i-1];
    if(id[i]<=n) insert(rt[i],rt[i],1,res,lower_bound(hsh+1,hsh+1+res,h[id[i]])-hsh);
  }
  RG int lastans=0;
  while(Q--){
    RG int u,x,k;scanf("%d%d%d",&u,&x,&k);
    u^=lastans,x^=lastans,k^=lastans;
    RG int Lca=jump(u,x);
    if(sum[rt[ed[Lca]]]-sum[rt[dfn[Lca]-1]]<k) puts("-1"),lastans=0;
    else lastans=query(rt[dfn[Lca]-1],rt[ed[Lca]],1,res,(sum[rt[ed[Lca]]]-sum[rt[dfn[Lca]-1]])-k+1),printf("%d\n",hsh[lastans]);
  }
  return 0;
}