Language: C++

#line 2 "lib/template.cpp"

#ifndef LOCAL
#pragma GCC target ("arch=skylake-avx512")
#endif
#include <algorithm>
#include <bitset>
#include <cassert>
#include <cmath>
#include <cstring>
#include <functional>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
using namespace std;
using ll = long long;
using ull = unsigned long long;
using VI = vector<int>;
using VVI = vector<vector<int>>;
using VLL = vector<ll>;
using VVLL = vector<vector<ll>>;
using VB = vector<bool>;
using PII = pair<int, int>;
using PLL = pair<ll, ll>;
constexpr int INF = 1000000007;
constexpr ll INF_LL = 1'000'000'000'000'000'007;
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
#define newl '\n'

// loops rep(until) / rep(var, until) / rep(var, from, until) / repr (reversed order)
#define OVERLOAD3(_1, _2, _3, name, ...) name
#define rep(...) OVERLOAD3(__VA_ARGS__, REPEAT_FROM_UNTIL, REPEAT_UNTIL, REPEAT)(__VA_ARGS__)
#define REPEAT(times) REPEAT_CNT(_repeat, __COUNTER__, times)
#define REPEAT_CNT(_repeat, cnt, times) REPEAT_CNT_CAT(_repeat, cnt, times)
#define REPEAT_CNT_CAT(_repeat, cnt, times) REPEAT_FROM_UNTIL(_repeat ## cnt, 0, times)
#define REPEAT_UNTIL(name, times) REPEAT_FROM_UNTIL(name, 0, times)
#define REPEAT_FROM_UNTIL(name, from, until) for (int name = from, name ## __until = (until); name < name ## __until; name++)
#define repr(...) OVERLOAD3(__VA_ARGS__, REPR_FROM_UNTIL, REPR_UNTIL, REPEAT)(__VA_ARGS__)
#define REPR_UNTIL(name, times) REPR_FROM_UNTIL(name, 0, times)
#define REPR_FROM_UNTIL(name, from, until) for (int name = (until)-1, name ## __from = (from); name >= name ## __from; name--)

template <typename T, typename U>
bool chmin(T& var, U x) { if (var > x) { var = x; return true; } else return false; }
template <typename T, typename U>
bool chmax(T& var, U x) { if (var < x) { var = x; return true; } else return false; }
ll power(ll e, ll t, ll mod = INF_LL) {
  ll res = 1; for (; t; t >>= 1, (e *= e) %= mod) if (t & 1) (res *= e) %= mod; return res;
}
template <typename T, typename U> T divceil(T m, U d) { return (m + d - 1) / d; }
template <typename T> vector<T> make_v(size_t a, T b) { return vector<T>(a, b); }
template <typename... Ts> auto make_v(size_t a, Ts... ts) {
  return vector<decltype(make_v(ts...))>(a, make_v(ts...));
}

// dump(...) for debug
#define repi(it, ds) for (auto it = ds.begin(); it != ds.end(); it++)
class DebugPrint { public: template <typename T> DebugPrint& operator <<(const T& v) {
#ifdef LOCAL
    cerr << v;
#endif
return *this; } } debugos; template <typename T> DebugPrint& operator<<(DebugPrint& os, const
vector<T>& vec) { os << "{"; for (int i = 0; i < vec.size(); i++) os << vec[i] << (i + 1 ==
vec.size() ? "" : ", "); os << "}"; return os; } template <typename T, typename U> DebugPrint&
operator<<(DebugPrint& os, const map<T, U>& map_var) { os << "{"; repi(itr, map_var) { os << *
itr; itr++; if (itr != map_var.end()) os << ", "; itr--; } os << "}"; return os; } template <
typename T> DebugPrint& operator<<(DebugPrint& os, const set<T>& set_var) { os << "{"; repi(
itr, set_var) { os << *itr; itr++; if (itr != set_var.end()) os << ", "; itr--; } os << "}";
return os; } template <typename T, typename U> DebugPrint& operator<<(DebugPrint& os, const
pair<T, U>& p) { os << "(" << p.first << ", " << p.second << ")"; return os; } void dump_func(
) { debugos << newl; } template <class Head, class... Tail> void dump_func(Head &&head, Tail
&&... tail) { debugos << head; if (sizeof...(Tail) > 0) { debugos << ", "; } dump_func(forward
<Tail>(tail)...); }
#ifdef LOCAL
#define dump(...) debugos << "  " << #__VA_ARGS__ << ": " << "[" << __LINE__ \
<< ":" << __FUNCTION__ << "]" << newl << "    ", dump_func(__VA_ARGS__)
#else
#define dump(...) ((void)0)
#endif


#line 2 "lib/data-structure/bit.cpp"

#line 4 "lib/data-structure/bit.cpp"

class BIT {
 public:
  int n;

 private:
  vector<ll> data;

 public:
  BIT() = default;
  explicit BIT(int n_ = 0) : n(n_), data(n_ + 1) {}
  template <typename Iter>
  explicit BIT(Iter first, Iter last) : n(distance(first, last)) {
    data = vector<ll>(n + 1);
    copy(first, last, data.begin() + 1);
    auto zeroix = data.begin() + 1;
    rep(i, n) {
      int j = i | (i+1);
      if (j < n) zeroix[j] += zeroix[i];
    }
  }
  void add(int p, ll v = 1) {
    p++;
    while (p <= n) {
      data[p] += v;
      p += p & -p;
    }
  }
  // sum over [0, p)
  ll sum(int p) const {
    ll res = 0;
    while (p) {
      res += data[p];
      p -= p & -p;
    }
    return res;
  }
  // sum over [l, r)
  ll sum(int l, int r) const { return sum(r) - sum(l); }
  void clear() { fill(all(data), 0); }
  void assign(int p, ll v) { add(p, v - sum(p, p + 1)); }
  // min i s.t. sum over [0, i) >= v -- or n+1 if failed
  // requires data[i] >= 0 for any i
  int lower_bound(ll v) const {
    if (v <= 0) return 0;
    int l = 0;
    for (int k = 1 << (32 - __builtin_clz(n) - 1); k; k >>= 1)
      if (l + k <= n and data[l + k] < v) v -= data[l += k];
    return l + 1;
  }
  // min i s.t. sum over [0, i) > v -- or n+1 if failed
  // requires data[i] >= 0 for any i
  int upper_bound(ll v) const { return lower_bound(v + 1); }
};
#line 3 "main.cpp"

int main() {
  cin.tie(nullptr); ios_base::sync_with_stdio(false);

  int n, q; cin >> n >> q;
  VI c(n); rep(i, n) cin >> c[i];
  vector<PII> lr(q); rep(i, q) cin >> lr[i].first >> lr[i].second;
  rep(i, q) lr[i].first--;

  const int sq = 700;
  vector<tuple<int, int, int>> lri(q);
  rep(i, q) lri[i] = make_tuple(lr[i].first / sq, lr[i].second, i);
  sort(all(lri));

  VI ans(q);

  BIT bit(n+1); VI cnt(n+1);
  int prev = 0;
  int lx = 0, rx = 0;
  for (auto [ls, r, i] : lri) {
    if (ls != prev) {
      bit.clear();
      cnt.clear();
      lx = rx = lr[i].first;
      prev = ls;
    }
    int l = lr[i].first;
    while (lx > l) if (cnt[c[--lx]]++ == 0) bit.add(c[lx], 1);
    while (lx < l) if (--cnt[c[lx++]] == 0) bit.add(c[lx-1], -1);
    while (rx < r) if (cnt[c[rx++]]++ == 0) bit.add(c[rx-1], 1);
    ans[i] = bit.sum(n);
  }
  rep(i, q) cout << ans[i] << "\n";
}


Compiler output:
In file included from /usr/include/c++/14/string:43,
                 from /usr/include/c++/14/bitset:52,
                 from lib/template.cpp:7:
/usr/include/c++/14/bits/allocator.h: In destructor 'std::_Vector_base<long long int, std::allocator<long long int> >::_Vector_impl::~_Vector_impl()':
/usr/include/c++/14/bits/allocator.h:182:7: error: inlining failed in call to 'always_inline' 'std::allocator< <template-parameter-1-1> >::~allocator() noexcept [with _Tp = long long int]': target specific option mismatch
  182 |       ~allocator() _GLIBCXX_NOTHROW { }
      |       ^
In file included from /usr/include/c++/14/vector:66,
                 from /usr/include/c++/14/functional:64,
                 from lib/template.cpp:11:
/usr/include/c++/14/bits/stl_vector.h:132:14: note: called from here
  132 |       struct _Vector_impl
      |              ^~~~~~~~~~~~