#include<bits/stdc++.h>
namespace {
#pragma GCC diagnostic ignored "-Wunused-function"
#include<atcoder/all>
#pragma GCC diagnostic warning "-Wunused-function"
using namespace std;
using namespace atcoder;
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; i--)
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } else return false; }
template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } else return false; }
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;

template <class S,
          S (*op)(S, S),
          S (*e)(),
          class F,
          bool (*mappable)(F, S),
          S (*mapping)(F, S),
          F (*composition)(F, F),
          F (*id)()>
struct segtree_beats {
  public:
    segtree_beats() : segtree_beats(0) {}
    explicit segtree_beats(int n) : segtree_beats(std::vector<S>(n, e())) {}
    explicit segtree_beats(const std::vector<S>& v) : _n(int(v.size())) {
        log = __lg(_n - 1) + 1;
        size = 1 << log;
        d = std::vector<S>(2 * size, e());
        lz = std::vector<F>(size, id());
        for (int i = 0; i < _n; i++) d[size + i] = v[i];
        for (int i = size - 1; i >= 1; i--) {
            update(i);
        }
    }

    void set(int p, S x) {
        assert(0 <= p && p < _n);
        p += size;
        for (int i = log; i >= 1; i--) push(p >> i);
        d[p] = x;
        for (int i = 1; i <= log; i++) update(p >> i);
    }

    S get(int p) {
        assert(0 <= p && p < _n);
        p += size;
        for (int i = log; i >= 1; i--) push(p >> i);
        return d[p];
    }

    S prod(int l, int r) {
        assert(0 <= l && l <= r && r <= _n);
        if (l == r) return e();

        l += size;
        r += size;

        for (int i = log; i >= 1; i--) {
            if (((l >> i) << i) != l) push(l >> i);
            if (((r >> i) << i) != r) push((r - 1) >> i);
        }

        S sml = e(), smr = e();
        while (l < r) {
            if (l & 1) sml = op(sml, d[l++]);
            if (r & 1) smr = op(d[--r], smr);
            l >>= 1;
            r >>= 1;
        }

        return op(sml, smr);
    }

    S all_prod() { return d[1]; }

    void apply(int p, F f) {
        assert(0 <= p && p < _n);
        p += size;
        for (int i = log; i >= 1; i--) push(p >> i);
        d[p] = mapping(f, d[p]);
        for (int i = 1; i <= log; i++) update(p >> i);
    }
    void apply(int l, int r, F f) {
        assert(0 <= l && l <= r && r <= _n);
        if (l == r) return;

        l += size;
        r += size;

        for (int i = log; i >= 1; i--) {
            if (((l >> i) << i) != l) push(l >> i);
            if (((r >> i) << i) != r) push((r - 1) >> i);
        }

        {
            int l2 = l, r2 = r;
            while (l < r) {
                if (l & 1) all_apply(l++, f);
                if (r & 1) all_apply(--r, f);
                l >>= 1;
                r >>= 1;
            }
            l = l2;
            r = r2;
        }

        for (int i = 1; i <= log; i++) {
            if (((l >> i) << i) != l) update(l >> i);
            if (((r >> i) << i) != r) update((r - 1) >> i);
        }
    }

    template <bool (*g)(S)> int max_right(int l) {
        return max_right(l, [](S x) { return g(x); });
    }
    template <class G> int max_right(int l, G g) {
        assert(0 <= l && l <= _n);
        assert(g(e()));
        if (l == _n) return _n;
        l += size;
        for (int i = log; i >= 1; i--) push(l >> i);
        S sm = e();
        do {
            while (l % 2 == 0) l >>= 1;
            if (!g(op(sm, d[l]))) {
                while (l < size) {
                    push(l);
                    l = (2 * l);
                    if (g(op(sm, d[l]))) {
                        sm = op(sm, d[l]);
                        l++;
                    }
                }
                return l - size;
            }
            sm = op(sm, d[l]);
            l++;
        } while ((l & -l) != l);
        return _n;
    }

    template <bool (*g)(S)> int min_left(int r) {
        return min_left(r, [](S x) { return g(x); });
    }
    template <class G> int min_left(int r, G g) {
        assert(0 <= r && r <= _n);
        assert(g(e()));
        if (r == 0) return 0;
        r += size;
        for (int i = log; i >= 1; i--) push((r - 1) >> i);
        S sm = e();
        do {
            r--;
            while (r > 1 && (r % 2)) r >>= 1;
            if (!g(op(d[r], sm))) {
                while (r < size) {
                    push(r);
                    r = (2 * r + 1);
                    if (g(op(d[r], sm))) {
                        sm = op(d[r], sm);
                        r--;
                    }
                }
                return r + 1 - size;
            }
            sm = op(d[r], sm);
        } while ((r & -r) != r);
        return 0;
    }

  private:
    int _n, size, log;
    std::vector<S> d;
    std::vector<F> lz;

    void update(int k) { d[k] = op(d[2 * k], d[2 * k + 1]); }
    void all_apply(int k, F f) {
        if (k < size) {
            lz[k] = composition(f, lz[k]);
            if (mappable(f, d[k])) {
                d[k] = mapping(f, d[k]);
            } else {
                push(k);
                update(k);
            }
        } else {
            d[k] = mapping(f, d[k]);
        }
    }
    void push(int k) {
        all_apply(2 * k, lz[k]);
        all_apply(2 * k + 1, lz[k]);
        lz[k] = id();
    }
};

struct S {
  int mn1, cnt, mn2;
  ll sm;
};
S op(S x, S y) {
  if (x.mn1 > y.mn1) swap(x, y);
  if (x.mn1 == y.mn1) x.cnt += y.cnt, chmin(x.mn2, y.mn2);
  else chmin(x.mn2, y.mn1);
  x.sm += y.sm;
  return x;
}
constexpr int INF = 1001001001;
S e() { return {INF, 0, INF, 0LL}; }
bool mappable(int f, S x) { return f < x.mn2; }
S mapping(int f, S x) {
  if (f > x.mn1) {
    x.sm += ll(f - x.mn1) * x.cnt;
    x.mn1 = f;
  }
  return x;
}
int composition(int f, int g) { return max(f, g); }
int id() { return -1; }

} int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, k, q;
  cin >> n >> k >> q;
  VI a(n);
  rep(i, n) cin >> a[i];
  vector<tuple<int, int, ll>> lrx(k), ask(q);
  for (auto& [l, r, x] : lrx) cin >> l >> r >> x, l--;
  for (auto& [l, r, x] : ask) cin >> l >> r >> x, l--;
  VI l(q, -1), r(q, k + 1);
  while (true) {
    VVI qs(k+1);
    bool done = true;
    rep(iq, q) if (r[iq] - l[iq] > 1) {
      qs[(l[iq] + r[iq]) / 2].emplace_back(iq);
      done = false;
    }
    if (done) break;
    segtree_beats<S, op, e, int, mappable, mapping, composition, id> seg([&]() {
      vector<S> init(n);
      rep(i, n) init[i] = S{a[i], 1, INF, a[i]};
      return init;
    }());
    rep(i, k + 1) {
      for (int iq : qs[i]) {
        auto [li, ri, x] = ask[iq];
        (seg.prod(li, ri).sm >= x ? r[iq] : l[iq]) = i;
      }
      if (i < k) {
        auto [li, ri, x] = lrx[i];
        seg.apply(li, ri, x);
      }
    }
  }
  rep(i, q) {
    int ans = r[i];
    if (ans == k + 1) ans = -1;
    cout << ans << '\n';
  }
}