#include<bits/stdc++.h>
#include<atcoder/all>
using namespace std;
using namespace atcoder;
typedef long long int ll;
typedef long double ld;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<vvl> vvvl;
typedef vector<vvvl> vvvvl;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef vector<vvb> vvvb;
typedef vector<vvvb> vvvvb;
typedef pair<ll,ll> pl;
typedef pair<ll,pl> ppl;
typedef pair<ll,ppl> pppl;
typedef pair<ll,pppl> pppppl;
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(b)-1;i>=(a);i--)
#define all(a) begin(a),end(a)
#define sz(a) (int)(a).size()
#define F first
#define S second
#define bs(A,x) binary_search(all(A),x)
#define lb(A,x) (ll)(lower_bound(all(A),x)-A.begin())
#define ub(A,x) (ll)(upper_bound(all(A),x)-A.begin())
#define cou(A,x) (ll)(upper_bound(all(A),x)-lower_bound(all(A),x))
template<typename T>using min_priority_queue=priority_queue<T,vector<T>,greater<T>>;
template<class T>bool chmax(T&a,T b){if(a<b){a=b;return 1;}return 0;}
template<class T>bool chmin(T&a,T b){if(b<a){a=b;return 1;}return 0;}
//*
using mint=modint998244353;
const ll mod=998244353;
//*/
/*
using mint=modint1000000007;
const ll mod=1000000007;
//*/
//using mint=modint;
//*
typedef vector<mint> vm;
typedef vector<vm> vvm;
typedef vector<vvm> vvvm;
typedef vector<vvvm> vvvvm;
ostream&operator<<(ostream&os,mint a){os<<a.val();return os;}
istream&operator>>(istream&is,mint&a){int x;is>>x;a=mint(x);return is;}
//*/
template<typename T1,typename T2>ostream&operator<<(ostream&os,pair<T1,T2>p){os<<p.F<<" "<<p.S;return os;}
template<typename T1,typename T2>istream&operator>>(istream&is,pair<T1,T2>&p){is>>p.F>>p.S;return is;}
template<typename T>ostream&operator<<(ostream&os,vector<T>v){rep(i,0,sz(v))os<<v[i]<<(i+1!=sz(v)?" ":"");return os;}
template<typename T>istream&operator>>(istream&is,vector<T>&v){for(T&in:v)is>>in;return is;}

// Segment Tree Beats
// - l<=i<r について、 A_i の値を min(A_i, x) に更新
// - l<=i<r について、 A_i の値を max(A_i, x) に更新
// - l<=i<r の中の A_i の最大値を求める
// - l<=i<r の中の A_i の最小値を求める
// - l<=i<r の A_i の和を求める
// - l<=i<r について、 A_i の値に x を加える
// - l<=i<r について、 A_i の値を x に更新

class SegmentTree {
  const ll inf = 1e18;
  int n, n0;
  ll max_v[4*10003], smax_v[4*10003], max_c[4*10003];
  ll min_v[4*10003], smin_v[4*10003], min_c[4*10003];
  ll sum[4*10003];
  ll len[4*10003], ladd[4*10003], lval[4*10003];

  void update_node_max(int k, ll x) {
    sum[k] += (x - max_v[k]) * max_c[k];

    if(max_v[k] == min_v[k]) {
      max_v[k] = min_v[k] = x;
    } else if(max_v[k] == smin_v[k]) {
      max_v[k] = smin_v[k] = x;
    } else {
      max_v[k] = x;
    }

    if(lval[k] != inf && x < lval[k]) {
      lval[k] = x;
    }
  }
  void update_node_min(int k, ll x) {
    sum[k] += (x - min_v[k]) * min_c[k];

    if(max_v[k] == min_v[k]) {
      max_v[k] = min_v[k] = x;
    } else if(smax_v[k] == min_v[k]) {
      min_v[k] = smax_v[k] = x;
    } else {
      min_v[k] = x;
    }

    if(lval[k] != inf && lval[k] < x) {
      lval[k] = x;
    }
  }

  void push(int k) {

    if(n0-1 <= k) return;

    if(lval[k] != inf) {
      updateall(2*k+1, lval[k]);
      updateall(2*k+2, lval[k]);
      lval[k] = inf;
      return;
    }

    if(ladd[k] != 0) {
      addall(2*k+1, ladd[k]);
      addall(2*k+2, ladd[k]);
      ladd[k] = 0;
    }

    if(max_v[k] < max_v[2*k+1]) {
      update_node_max(2*k+1, max_v[k]);
    }
    if(min_v[2*k+1] < min_v[k]) {
      update_node_min(2*k+1, min_v[k]);
    }

    if(max_v[k] < max_v[2*k+2]) {
      update_node_max(2*k+2, max_v[k]);
    }
    if(min_v[2*k+2] < min_v[k]) {
      update_node_min(2*k+2, min_v[k]);
    }
  }

  void update(int k) {
    sum[k] = sum[2*k+1] + sum[2*k+2];

    if(max_v[2*k+1] < max_v[2*k+2]) {
      max_v[k] = max_v[2*k+2];
      max_c[k] = max_c[2*k+2];
      smax_v[k] = max(max_v[2*k+1], smax_v[2*k+2]);
    } else if(max_v[2*k+1] > max_v[2*k+2]) {
      max_v[k] = max_v[2*k+1];
      max_c[k] = max_c[2*k+1];
      smax_v[k] = max(smax_v[2*k+1], max_v[2*k+2]);
    } else {
      max_v[k] = max_v[2*k+1];
      max_c[k] = max_c[2*k+1] + max_c[2*k+2];
      smax_v[k] = max(smax_v[2*k+1], smax_v[2*k+2]);
    }

    if(min_v[2*k+1] < min_v[2*k+2]) {
      min_v[k] = min_v[2*k+1];
      min_c[k] = min_c[2*k+1];
      smin_v[k] = min(smin_v[2*k+1], min_v[2*k+2]);
    } else if(min_v[2*k+1] > min_v[2*k+2]) {
      min_v[k] = min_v[2*k+2];
      min_c[k] = min_c[2*k+2];
      smin_v[k] = min(min_v[2*k+1], smin_v[2*k+2]);
    } else {
      min_v[k] = min_v[2*k+1];
      min_c[k] = min_c[2*k+1] + min_c[2*k+2];
      smin_v[k] = min(smin_v[2*k+1], smin_v[2*k+2]);
    }
  }

  void _update_min(ll x, int a, int b, int k, int l, int r) {
    if(b <= l || r <= a || max_v[k] <= x) {
      return;
    }
    if(a <= l && r <= b && smax_v[k] < x) {
      update_node_max(k, x);
      return;
    }

    push(k);
    _update_min(x, a, b, 2*k+1, l, (l+r)/2);
    _update_min(x, a, b, 2*k+2, (l+r)/2, r);
    update(k);
  }

  void _update_max(ll x, int a, int b, int k, int l, int r) {
    if(b <= l || r <= a || x <= min_v[k]) {
      return;
    }
    if(a <= l && r <= b && x < smin_v[k]) {
      update_node_min(k, x);
      return;
    }

    push(k);
    _update_max(x, a, b, 2*k+1, l, (l+r)/2);
    _update_max(x, a, b, 2*k+2, (l+r)/2, r);
    update(k);
  }

  void addall(int k, ll x) {
    max_v[k] += x;
    if(smax_v[k] != -inf) smax_v[k] += x;
    min_v[k] += x;
    if(smin_v[k] != inf) smin_v[k] += x;

    sum[k] += len[k] * x;
    if(lval[k] != inf) {
      lval[k] += x;
    } else {
      ladd[k] += x;
    }
  }

  void updateall(int k, ll x) {
    max_v[k] = x; smax_v[k] = -inf;
    min_v[k] = x; smin_v[k] = inf;
    max_c[k] = min_c[k] = len[k];

    sum[k] = x * len[k];
    lval[k] = x; ladd[k] = 0;
  }

  void _add_val(ll x, int a, int b, int k, int l, int r) {
    if(b <= l || r <= a) {
      return;
    }
    if(a <= l && r <= b) {
      addall(k, x);
      return;
    }

    push(k);
    _add_val(x, a, b, 2*k+1, l, (l+r)/2);
    _add_val(x, a, b, 2*k+2, (l+r)/2, r);
    update(k);
  }

  void _update_val(ll x, int a, int b, int k, int l, int r) {
    if(b <= l || r <= a) {
      return;
    }
    if(a <= l && r <= b) {
      updateall(k, x);
      return;
    }

    push(k);
    _update_val(x, a, b, 2*k+1, l, (l+r)/2);
    _update_val(x, a, b, 2*k+2, (l+r)/2, r);
    update(k);
  }

  ll _query_max(int a, int b, int k, int l, int r) {
    if(b <= l || r <= a) {
      return -inf;
    }
    if(a <= l && r <= b) {
      return max_v[k];
    }
    push(k);
    ll lv = _query_max(a, b, 2*k+1, l, (l+r)/2);
    ll rv = _query_max(a, b, 2*k+2, (l+r)/2, r);
    return max(lv, rv);
  }

  ll _query_min(int a, int b, int k, int l, int r) {
    if(b <= l || r <= a) {
      return inf;
    }
    if(a <= l && r <= b) {
      return min_v[k];
    }
    push(k);
    ll lv = _query_min(a, b, 2*k+1, l, (l+r)/2);
    ll rv = _query_min(a, b, 2*k+2, (l+r)/2, r);
    return min(lv, rv);
  }

  ll _query_sum(int a, int b, int k, int l, int r) {
    if(b <= l || r <= a) {
      return 0;
    }
    if(a <= l && r <= b) {
      return sum[k];
    }
    push(k);
    ll lv = _query_sum(a, b, 2*k+1, l, (l+r)/2);
    ll rv = _query_sum(a, b, 2*k+2, (l+r)/2, r);
    return lv + rv;
  }

public:
  SegmentTree(int n) {
    SegmentTree(n, nullptr);
  }

  SegmentTree(int n, ll *a) : n(n) {
    n0 = 1;
    while(n0 < n) n0 <<= 1;

    for(int i=0; i<2*n0; ++i) ladd[i] = 0, lval[i] = inf;
    len[0] = n0;
    for(int i=0; i<n0-1; ++i) len[2*i+1] = len[2*i+2] = (len[i] >> 1);

    for(int i=0; i<n; ++i) {
      max_v[n0-1+i] = min_v[n0-1+i] = sum[n0-1+i] = (a != nullptr ? a[i] : 0);
      smax_v[n0-1+i] = -inf;
      smin_v[n0-1+i] = inf;
      max_c[n0-1+i] = min_c[n0-1+i] = 1;
    }

    for(int i=n; i<n0; ++i) {
      max_v[n0-1+i] = smax_v[n0-1+i] = -inf;
      min_v[n0-1+i] = smin_v[n0-1+i] = inf;
      max_c[n0-1+i] = min_c[n0-1+i] = 0;
    }
    for(int i=n0-2; i>=0; i--) {
      update(i);
    }
  }

  // range minimize query
  void update_min(int a, int b, ll x) {
    _update_min(x, a, b, 0, 0, n0);
  }

  // range maximize query
  void update_max(int a, int b, ll x) {
    _update_max(x, a, b, 0, 0, n0);
  }

  // range add query
  void add_val(int a, int b, ll x) {
    _add_val(x, a, b, 0, 0, n0);
  }

  // range update query
  void update_val(int a, int b, ll x) {
    _update_val(x, a, b, 0, 0, n0);
  }

  // range minimum query
  ll query_max(int a, int b) {
    return _query_max(a, b, 0, 0, n0);
  }

  // range maximum query
  ll query_min(int a, int b) {
    return _query_min(a, b, 0, 0, n0);
  }

  // range sum query
  ll query_sum(int a, int b) {
    return _query_sum(a, b, 0, 0, n0);
  }
};

int main(){
  cin.tie(0)->sync_with_stdio(0);
  cin.exceptions(cin.failbit);
  ll N,K,Q;cin>>N>>K>>Q;
  vl A(N);cin>>A;
  vl L(K),R(K),X(K);
  rep(i,0,K)cin>>L[i]>>R[i]>>X[i];
  rep(i,0,K)L[i]--;
  vl l(Q),r(Q),x(Q);
  rep(i,0,Q)cin>>l[i]>>r[i]>>x[i];
  rep(i,0,Q)l[i]--;
  
  vl LL(Q,-1),RR(Q,K+1);
  rep(_,0,14){
	ll a[N];
	rep(i,0,N)a[i]=A[i];
	SegmentTree seg(N,a);
	vvl E(K+1);
	rep(i,0,Q)if(RR[i]>0)E[(LL[i]+RR[i])/2].emplace_back(i);
	rep(i,0,K+1){
		for(auto q:E[i]){
			if(seg.query_sum(l[q],r[q])>=x[q])RR[q]=i;
			else LL[q]=i;
		}
		if(i==K)break;
		seg.update_max(L[i],R[i],X[i]);
	}
  }
  rep(i,0,Q){
  	if(RR[i]==K+1)cout<<-1<<endl;
  	else cout<<RR[i]<<endl;
  }
  return 0;
}