Problem p02599 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <bits/stdc++.h>
using namespace std;
#define ll long long int
#define rep(i, s, f) for (i = s; i < f; i++)
#define print(v)                                                               \\
  for (auto &z : v)                                                            \\
    cout << z << ' ';                                                          \\
  cout << '\\n'
#define db cout << "db: "
#define pb push_back
#define pii pair<int, int>
#define F first
#define S second
#define B begin()
#define E end()
#define all(v) v.B, v.E
#define sz(v) (int)((v).size())
#define vi vector<int>
#define vii vector<pair<int, int>>
#define boost                                                                  \\
  ios_base::sync_with_stdio(false);                                            \\
  cin.tie(0);                                                                  \\
  cout.tie(0)
#define clk1 clock_t start_time = clock()
#define clk2 cout << (clock() - start_time) / (double)CLOCKS_PER_SEC
#define clean(arr) memset(arr, 0, sizeof(arr))
#define mod 1000000007
#define mod2 998244353
#define space 500005
//<<fixed << setprecision(9)

int arr[space];
int cnt[space];
int distinct;

const int block_size = 700;

struct Query {
  int l, r, idx;
  bool operator<(Query other) const {
    if (l / block_size != other.l / block_size)
      return l < other.l;
    return ((l / block_size) & 1) ? r < other.r : r > other.r;
  }
};

void add(int &x) {
  cnt[arr[x]]++;
  if (cnt[arr[x]] == 1)
    distinct++;
}
void remove(int &x) {
  cnt[arr[x]]--;
  if (cnt[arr[x]] == 0)
    distinct--;
}

int main() {
  int n, i, j, t;
  boost;

  cin >> n >> t;

  rep(i, 1, n + 1) cin >> arr[i];

  Query Q[t];
  int ans[t];
  rep(i, 0, t) {
    int l, r;
    cin >> l >> r;
    Q[i] = {l, r, i};
  }
  sort(Q, Q + t);

  int cur_l = 1;
  int cur_r = 0;

  for (Query q : Q) {
    while (cur_l > q.l) {
      cur_l--;
      add(cur_l);
    }
    while (cur_r < q.r) {
      cur_r++;
      add(cur_r);
    }
    while (cur_l < q.l) {
      remove(cur_l);
      cur_l++;
    }
    while (cur_r > q.r) {
      remove(cur_r);
      cur_r--;
    }
    ans[q.idx] = distinct;
  }

  rep(i, 0, t) cout << ans[i] << '\\n';

  return 0;
}


Error: TLE

Fixed submission:

#include "bits/stdc++.h"
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const int INF = 1e9;
const ll LINF = 1e18;
inline ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; }
inline ll lcm(ll a, ll b) { return a / gcd(a, b) * b; }
template <class S, class T>
ostream &operator<<(ostream &out, const pair<S, T> &o) {
  out << "(" << o.first << "," << o.second << ")";
  return out;
}
template <class T> ostream &operator<<(ostream &out, const vector<T> &V) {
  for (int i = 0; i < V.size(); i++) {
    out << V[i];
    if (i != V.size() - 1)
      out << " ";
  }
  return out;
}
template <class T>
ostream &operator<<(ostream &out, const vector<vector<T>> &Mat) {
  for (int i = 0; i < Mat.size(); i++) {
    if (i != 0)
      out << endl;
    out << Mat[i];
  }
  return out;
}
template <class S, class T>
ostream &operator<<(ostream &out, const map<S, T> &mp) {
  out << "{ ";
  for (auto it = mp.begin(); it != mp.end(); it++) {
    out << it->first << ":" << it->second;
    if (mp.size() - 1 != distance(mp.begin(), it))
      out << ", ";
  }
  out << " }";
  return out;
}
template <typename T> vector<T> make_v(size_t a) { return vector<T>(a); }
template <typename T, typename... Ts> auto make_v(size_t a, Ts... ts) {
  return vector<decltype(make_v<T>(ts...))>(a, make_v<T>(ts...));
}
template <typename T, typename V>
typename enable_if<is_class<T>::value == 0>::type fill_v(T &t, const V &v) {
  t = v;
}
template <typename T, typename V>
typename enable_if<is_class<T>::value != 0>::type fill_v(T &t, const V &v) {
  for (auto &e : t)
    fill_v(e, v);
}
/*
 <url:>
 問題文============================================================
 =================================================================
 解説=============================================================
 ================================================================
 */

struct Mo {
  using add_func = function<void(int &)>;
  using del_func = function<void(int &)>;
  using rem_func = function<void(int &)>;

  int BlockSZ;
  vector<int> L, R, order;
  Mo(int N, int Q, int BlockSZ = -1) : BlockSZ((int)sqrt(N)), order(Q) {
    if (BlockSZ != -1)
      this->BlockSZ = BlockSZ;
    iota(order.begin(), order.end(), 0);
  }

  // [l,r)  : 0-index
  void add(int l, int r) {
    L.emplace_back(l);
    R.emplace_back(r);
  }

  void run(const add_func &add, const del_func &del, const rem_func &rem) {
    // assert(left.size() == order.size());
    sort(order.begin(), order.end(), [&](int l, int r) {
      int lblock = L[l] / BlockSZ, rblock = L[r] / BlockSZ;
      if (lblock != rblock)
        return l < r;
      return (lblock & 1) ? R[l] < R[r] : R[l] > R[r];
    });
    int nl = 0, nr = 0;
    for (auto idx : order) {
      while (nl > L[idx]) {
        nl--;
        add(nl);
      }
      while (nr < R[idx]) {
        add(nr);
        nr++;
      }
      while (nl < L[idx]) {
        del(nl);
        nl++;
      }
      while (nr > R[idx]) {
        nr--;
        del(nr);
      }
      rem(idx);
    }
  }
};

template <class Type> Type solve(Type res = Type()) {
  int N, Q;
  cin >> N >> Q;
  vector<int> c(N);
  for (auto &in : c)
    cin >> in;
  Mo mo(N, Q, 700);
  for (int i = 0; i < Q; i++) {
    int l, r;
    cin >> l >> r;
    l--;
    mo.add(l, r);
  }

  vector<int> ans(Q);
  vector<int> cnt(N + 1);
  int sum = 0;
  auto add = [&](int &id) {
    if (cnt[c[id]] == 0)
      sum++;
    cnt[c[id]]++;
  };
  auto del = [&](int &id) {
    cnt[c[id]]--;
    if (cnt[c[id]] == 0)
      sum--;
  };
  auto rem = [&](int &id) { ans[id] = sum; };

  mo.run(add, del, rem);
  for (int i = 0; i < Q; i++) {
    cout << ans[i] << "\\n";
  }

  return res;
}
int main(void) {
  cin.tie(0);
  ios_base::sync_with_stdio(false);
  cout.tie(0);
  solve(0);
  // cout << fixed << setprecision(15) << solve<ll>() << endl;
  return 0;
}