Problem p02599 (C++)

Buggy submission (status: Runtime Error):
#include <algorithm>
#include <iostream>
#include <numeric>
#include <string>
#include <tuple>
#include <utility>
#include <vector>

#define REP(i, a, b) for (int i = int(a); i < int(b); i++)
using namespace std;
using ll = long long int;
using P = pair<ll, ll>;

// clang-format off
#ifdef _DEBUG_
#define dump(...) do{ cerr << __LINE__ << ":\t" << #__VA_ARGS__ << " = "; PPPPP(__VA_ARGS__); cerr << endl; } while(false)
template<typename T> void PPPPP(T t) { cerr << t; }
template<typename T, typename... S> void PPPPP(T t, S... s) { cerr << t << ", "; PPPPP(s...); }
#else
#define dump(...) do{ } while(false)
#endif
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...)); }
template<typename T> bool chmin(T &a, T b) { if (a > b) {a = b; return true; } return false; }
template<typename T> bool chmax(T &a, T b) { if (a < b) {a = b; return true; } return false; }
template<typename T> void print(T a) { cout << a << endl; }
template<typename T, typename... Ts> void print(T a, Ts... ts) { cout << a << ' '; print(ts...); }
template<typename T> istream &operator,(istream &in, T &t) { return in >> t; }
// clang-format on

#include <functional>
template <typename T> class SegmentTreeOneAll {
  using Func = function<T(T, T)>;

public:
  vector<T> data;
  int n;
  T init;
  Func update_func;
  Func query_func;
  SegmentTreeOneAll(int _n, T _init, Func up, Func qu) {
    init = _init;
    update_func = up;
    query_func = qu;
    for (n = 1; n < _n; n *= 2)
      ;
    data.resize(2 * n - 1, init);
  }
  void update(int pos, T val) {
    pos += n - 1;
    data[pos] = update_func(data[pos], val);
    while (pos > 0) {
      pos = (pos - 1) / 2;
      data[pos] = query_func(data[2 * pos + 1], data[2 * pos + 2]);
    }
  }
  T query(int l, int r) {
    T resL = init, resR = init;
    for (l += n - 1, r += n - 1; l < r; l = l / 2, r = (r - 1) / 2) {
      if (!(l & 1)) {
        resL = query_func(resL, data[l]);
      }
      if (!(r & 1)) {
        resR = query_func(data[r - 1], resR);
      }
    }
    return query_func(resL, resR);
  }
};

int main() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  int n, q;
  cin, n, q;
  vector<int> c(n);
  REP(i, 0, n) {
    cin, c[i];
    c[i]--;
  }

  vector<vector<P>> Q(n);
  REP(i, 0, q) {
    int l, r;
    cin, l, r;
    Q[r - 1].emplace_back(l - 1, i);
  }

  vector<int> ans(n);
  auto add = [](ll a, ll b) { return a + b; };
  auto update = [](ll a, ll b) { return b; };
  SegmentTreeOneAll<ll> seg(n, 0LL, update, add);
  vector<int> last(n, -1);

  REP(i, 0, n) {
    if (last[c[i]] != -1) {
      seg.update(last[c[i]], 0);
    }
    seg.update(i, 1);
    last[c[i]] = i;
    for (auto [l, pos] : Q[i]) {
      ans[pos] = seg.query(l, i + 1);
    }
  }

  REP(i, 0, q) { print(ans[i]); }

  return 0;
}


Fixed submission:
#include <algorithm>
#include <iostream>
#include <numeric>
#include <string>
#include <tuple>
#include <utility>
#include <vector>

#define REP(i, a, b) for (int i = int(a); i < int(b); i++)
using namespace std;
using ll = long long int;
using P = pair<ll, ll>;

// clang-format off
#ifdef _DEBUG_
#define dump(...) do{ cerr << __LINE__ << ":\t" << #__VA_ARGS__ << " = "; PPPPP(__VA_ARGS__); cerr << endl; } while(false)
template<typename T> void PPPPP(T t) { cerr << t; }
template<typename T, typename... S> void PPPPP(T t, S... s) { cerr << t << ", "; PPPPP(s...); }
#else
#define dump(...) do{ } while(false)
#endif
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...)); }
template<typename T> bool chmin(T &a, T b) { if (a > b) {a = b; return true; } return false; }
template<typename T> bool chmax(T &a, T b) { if (a < b) {a = b; return true; } return false; }
template<typename T> void print(T a) { cout << a << endl; }
template<typename T, typename... Ts> void print(T a, Ts... ts) { cout << a << ' '; print(ts...); }
template<typename T> istream &operator,(istream &in, T &t) { return in >> t; }
// clang-format on

#include <functional>
template <typename T> class SegmentTreeOneAll {
  using Func = function<T(T, T)>;

public:
  vector<T> data;
  int n;
  T init;
  Func update_func;
  Func query_func;
  SegmentTreeOneAll(int _n, T _init, Func up, Func qu) {
    init = _init;
    update_func = up;
    query_func = qu;
    for (n = 1; n < _n; n *= 2)
      ;
    data.resize(2 * n - 1, init);
  }
  void update(int pos, T val) {
    pos += n - 1;
    data[pos] = update_func(data[pos], val);
    while (pos > 0) {
      pos = (pos - 1) / 2;
      data[pos] = query_func(data[2 * pos + 1], data[2 * pos + 2]);
    }
  }
  T query(int l, int r) {
    T resL = init, resR = init;
    for (l += n - 1, r += n - 1; l < r; l = l / 2, r = (r - 1) / 2) {
      if (!(l & 1)) {
        resL = query_func(resL, data[l]);
      }
      if (!(r & 1)) {
        resR = query_func(data[r - 1], resR);
      }
    }
    return query_func(resL, resR);
  }
};

int main() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  int n, q;
  cin, n, q;
  vector<int> c(n);
  REP(i, 0, n) {
    cin, c[i];
    c[i]--;
  }

  vector<vector<P>> Q(n);
  REP(i, 0, q) {
    int l, r;
    cin, l, r;
    Q[r - 1].emplace_back(l - 1, i);
  }

  vector<int> ans(q);
  auto add = [](ll a, ll b) { return a + b; };
  auto update = [](ll a, ll b) { return b; };
  SegmentTreeOneAll<ll> seg(n, 0LL, update, add);
  vector<int> last(n, -1);

  REP(i, 0, n) {
    if (last[c[i]] != -1) {
      seg.update(last[c[i]], 0);
    }
    seg.update(i, 1);
    last[c[i]] = i;
    for (auto [l, pos] : Q[i]) {
      ans[pos] = seg.query(l, i + 1);
    }
  }

  REP(i, 0, q) { print(ans[i]); }

  return 0;
}