#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
typedef long long int ll;
typedef vector<ll> vi;
typedef vector<vector<ll>> vvi;
typedef pair<ll,ll> pi;
typedef map<ll,ll> mi;
typedef long double ld;
typedef vector<ld> vd;
typedef vector<vector<ld>> vvd;
typedef pair<ld,ld> pd;
#define ff first
#define ss second
#define srt(a) sort(a.begin(),a.end());
#define fip(k, n) for (ll i = k; i < n; i++)
#define fjp(k, n) for (ll j = k; j < n; j++)
#define fin(k, n) for (ll i = k; i >= n; i--)
#define fjn(k, n) for (ll j = k; j >= n; j--)
#define fp(k, n, m) for (ll k = n; k < m; k++)
#define fn(k, n, m) for (ll k = n; k >= m; k--)
#define ordered_set tree<pi, null_type,less< pi >, rb_tree_tag,tree_order_statistics_node_update>
#define totalOne(n) __builtin_popcount(n)
#define backZero(n) __builtin_ctzll(n)
#define frontZero(n) __builtin_clzll(n)
#define fx(k) for ( auto x : k )
#define test ll t;cin >> t;while (t--)
#define nli "\n"
// ==========================(debug)============================================================================================== //
#ifdef SAMI
#define debug(x) cerr<<#x;cerr<<" ";_printn(x);cerr<<nli;
#define debg() cerr<<nli;
#else
#define debug(x)
#define debg()
#endif
void _printn(ll x){ cerr<<x<<" "; }
void _printn(int x){ cerr<<x<<" "; }
void _printn(ld x){ cerr<<x<<" "; }
void _printn(double x){ cerr<<x<<" "; }
void _printn(string x){ cerr<<x<<" "; }
void _printn(char x){ cerr<<x<<" "; }
void _printn(bool x){ cerr<<x<<" "; }
template<class T,class V>void _printn(pair<T,V> vv);
template<class T> void _printn(vector<T> vv);
template<class T> void _printn(set<T> vv);
template<class T,class V> void _printn(map<T,V> vv);
template<class T> void _printn(multiset<T> vv);
template<class T,class V>void _printn(pair<T,V> vv){ cerr<<"( ";_printn(vv.ff);cerr<<",";_printn(vv.ss);cerr<<")";}
template<class T> void _printn(vector<T> vv){ cerr<<"[ "; for(auto xx:vv){ _printn(xx);cerr<<" "; } cerr<<"]"; };
template<class T> void _printn(set<T> vv){ cerr<<"{ "; for(auto xx:vv){ _printn(xx);cerr<<" "; } cerr<<"}"; };
template<class T> void _printn(multiset<T> vv){ cerr<<"{ "; for(auto xx:vv){ _printn(xx);cerr<<" "; } cerr<<"}"; };
template<class T,class V> void _printn(map<T,V> vv){ cerr<<"{ "; for(auto xx:vv){ _printn(xx);cerr<<" "; } cerr<<"}"; };
// ==========================(debug)============================================================================================== //
ll n,m,tp,tp2,res,cnt,sum,tptp,ans;
const ll mx = 1e5+5;
const ll mod = 1e9+7;
// ==========================(MOD)=============================================================================================== //
ll mod_add(ll aa,ll bb){ return ((aa%mod)+(bb%mod))%mod; }
ll mod_minus(ll aa,ll bb){ return (((aa%mod)-(bb%mod))+10*mod)%mod; }
ll mod_mul(ll aa,ll bb){ return ((aa%mod)*(bb%mod))%mod; }
ll mod_power(ll aa,ll bb){ aa%=mod; ll empowered = 1; bb%=mod-1; while(bb > 0){ if(bb & 1) empowered = mod_mul(empowered,aa); bb = bb >> 1; aa = mod_mul(aa,aa); } return empowered; }
ll mod_divi(ll aa,ll bb){ aa=mod_mul(aa,mod_power(bb,mod-2)); return aa; }
// ==========================(MOD)=============================================================================================== //
bool f = false;
set<ll> st[mx];
ll sr,de;
ll a[mx];
vi v,v2;
void init(int N, int D, int H[]) {
n = N;
fip(0,N)
a[i] = H[i];
return;
}
void curseChanges(int U, int A[], int B[]) {
fip(0,U){
sr = A[i];
de = B[i];
// debug(sr);
// debug(de);
if(st[sr].find(de)==st[sr].end())
st[sr].insert(de);
else
st[sr].erase(st[sr].find(de));
if(st[de].find(sr)==st[de].end())
st[de].insert(sr);
else
st[de].erase(st[de].find(sr));
// fjp(0,n){
// debug(st[j]);
// }
// debg()
}
return;
}
int question(int xx, int yy, int V) {
v.clear();
v2.clear();
debug(st[xx]);
debug(st[yy]);
fx(st[xx])
v.push_back(a[x]);
fx(st[yy])
v2.push_back(a[x]);
srt(v);
srt(v2);
debug(v);
debug(v2);
ans = 1e9;
if(!v.size() || !v2.size())return ans;
tp = 0;
tp2 = 0;
while(tp<(ll)v.size()) {
while(tp2+1<(ll)v2.size() && v2[tp2+1] <= v[tp])
tp2++;
ans = min(ans,abs(v[tp]-v2[tp2]));
if(tp2+1<(ll)v2.size())
ans = min(ans,abs(v[tp]-v2[tp2+1]));
tp++;
}
// fip(0,n){
// debug(st[i]);
// }
debg()
return ((int)ans);
}
#ifdef SAMI
int main(){
ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#ifdef SAMI
freopen("input1.txt", "r", stdin);
freopen("output1.txt", "w", stdout);
freopen("error1.txt", "w", stderr);
#endif // ONLINE_JUDGE
int N, D, U, Q;
std::cin >> N >> D >> U >> Q;
int *F = new int[N];
for (int i=0; i<N; i++)
std::cin >> F[i];
init(N, D, F);
int *A = new int[U], *B = new int[U];
for (int i=0; i<U; i++) {
std::cin >> A[i] >> B[i];
}
curseChanges(U, A, B);
bool correct = true;
for (int i=0; i<Q; i++) {
int X,Y,V,CorrectAnswer;
/*
std::cin >> X >> Y >> V >> CorrectAnswer;
int YourAnswer = question(X,Y,V);
if (YourAnswer != CorrectAnswer) {
std::cout << "WA! Question: " << i
<< " (X=" << X << ", Y=" << Y << ", V=" << V << ") "
<< "Your answer: " << YourAnswer
<< " Correct Answer: " << CorrectAnswer << std::endl;
correct = false;
} else {
std::cerr << YourAnswer << " - OK" << std::endl;
}
}
if (correct) {
std::cout << "Correct." << std::endl;
} else std::cout << "Incorrect." << std::endl;
*/
std::cin >> X >> Y >> V;
int YourAnswer = question(X,Y,V);
cout<<YourAnswer<<nli;
}
//cerr << "Time elapsed: " << setprecision(6) << 1000.0 * clock() / CLOCKS_PER_SEC << "ms\n";
return 0;
}
#endif
