Problem p02599 (C++)

Buggy submission (status: Runtime Error):
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx")
#pragma GCC optimize("unroll-loops")
// #pragma warning(disable : 4996)

#ifdef _MSC_VER
#include <intrin.h>
#define __builtin_popcount __popcnt
#define __builtin_popcountll __popcnt64
#endif

#include <limits.h>
#include <math.h>
#include <time.h>

#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <complex>
#include <cstdio>
#include <cstring>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

using namespace std;

#define REP(i, n) for (int i = 0; i < (n); ++i)
#define REPR(i, n) for (int i = n - 1; i >= 0; --i)
#define FOR(i, m, n) for (int i = m; i < n; ++i)
#define FORR(i, m, n) for (int i = m - 1; i >= n; --i)
#define SORT(v, n) sort(v, v + n);
#define VSORT(v) sort(v.begin(), v.end());
#define REVERSE(v, n) reverse(v, v + n);
#define VREVERSE(v) reverse(v.begin(), v.end())
#define ll long long
#define print(x) cout << (x) << '\n'
#define pe(x) cout << (x) << " "
#define DEBUG(x) cout << #x << ": " << x << endl
#define lb(v, n) lower_bound(v.begin(), v.end(), (n))
#define ub(v, n) upper_bound(v.begin(), v.end(), (n))
#define int long long
// #define double long double
#define all(x) (x).begin(), (x).end()
#define print_space(v)                                                         \
  REP(i, v.size()) cout << v[i] << " \n"[i == (int)v.size() - 1]
template <typename T1, typename T2> inline void chmin(T1 &a, T2 b) {
  if (a > b)
    a = b;
}
template <typename T1, typename T2> inline void chmax(T1 &a, T2 b) {
  if (a < b)
    a = b;
}
typedef pair<int, int> pii;
typedef pair<long long, long long> pll;
std::random_device rd;
std::mt19937 mt(rd());
constexpr ll MOD = 1e9 + 7;
constexpr int MAX = 500050;
const double pi = acos(-1);
constexpr double EPS = 1e-8;
constexpr ll LINF = 1e18 + 1;
constexpr int INF = 1e9 + 1;
// int dx[4] = { 0,0,-1,1 }, dy[4] = { 1,-1,0,0 };

template <typename T> struct SegmentTree {
  int n;
  T unit;
  vector<T> dat;
  function<T(T, T)> func;
  SegmentTree(const int N, T _unit, function<T(T, T)> _func)
      : unit(_unit), func(_func) {
    n = 1;
    // 簡単のため、要素数を2のべき乗に
    while (n < N)
      n *= 2;
    dat.assign(2 * n, unit);
  }

  void update(int k, T a) {
    k += n - 1; // 葉の節点
    dat[k] = a;
    // 上りながら更新
    while (k > 0) {
      k = (k - 1) / 2;
      dat[k] = func(dat[k * 2 + 1], dat[k * 2 + 2]);
    }
  }
  T _query(int a, int b, int k, int l, int r) {
    //[a,b)と[l,r)が交差していなければ、funcに影響を与えない値を返す
    if (r <= a || b <= l)
      return unit;
    //[a,b)が[l,r)を完全に含んでいれば、この節点の値
    if (a <= l && r <= b)
      return dat[k];
    else {
      T vl = _query(a, b, k * 2 + 1, l, (l + r) / 2);
      T vr = _query(a, b, k * 2 + 2, (l + r) / 2, r);
      return func(vl, vr);
    }
  }
  //[a,b)
  T query(int a, int b) { return _query(a, b, 0, 0, n); }
};
// auto f = [](int a, int b) {return a + b; };
// SegmentTree<int>seg(N,0,f);

int las[200020];
void solve() {
  int N, Q;
  cin >> N >> Q;
  vector<int> A(N);
  REP(i, N) cin >> A[i];
  vector<int> L(Q), R(Q);
  vector<pair<pii, int>> v;
  REP(i, Q) {
    cin >> L[i] >> R[i];
    L[i]--, R[i]--;
    v.push_back({{R[i], L[i]}, i});
  }
  REP(i, N + 1) { las[i] = -1; }
  VSORT(v);
  vector<int> ids;
  REP(i, Q) ids.push_back(v[i].second);
  auto f = [](int a, int b) { return a + b; };
  SegmentTree<int> seg(N + 1, 0, f);
  int idx = 0;
  vector<int> ans(Q);
  REP(r, N) {
    // DEBUG(r);
    int pos = las[A[r]];
    if (pos != -1) {
      seg.update(pos, seg.query(pos, pos + 1) - 1);
    }
    las[A[r]] = r;
    int id = ids[idx];
    seg.update(r, seg.query(r, r + 1) + 1);
    while (idx < Q && R[id] == r) {
      // DEBUG(idx);
      // DEBUG(id);
      int l = L[id];
      ans[id] = seg.query(l, r + 1);
      idx++;
      if (idx == Q)
        break;
      id = ids[idx];
    }
  }
  REP(i, Q) print(ans[i]);
}

signed main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  // int q;
  // cin >> q;
  // while (q--)
  solve();
}


Fixed submission:
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx")
#pragma GCC optimize("unroll-loops")
// #pragma warning(disable : 4996)

#ifdef _MSC_VER
#include <intrin.h>
#define __builtin_popcount __popcnt
#define __builtin_popcountll __popcnt64
#endif

#include <limits.h>
#include <math.h>
#include <time.h>

#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <complex>
#include <cstdio>
#include <cstring>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

using namespace std;

#define REP(i, n) for (int i = 0; i < (n); ++i)
#define REPR(i, n) for (int i = n - 1; i >= 0; --i)
#define FOR(i, m, n) for (int i = m; i < n; ++i)
#define FORR(i, m, n) for (int i = m - 1; i >= n; --i)
#define SORT(v, n) sort(v, v + n);
#define VSORT(v) sort(v.begin(), v.end());
#define REVERSE(v, n) reverse(v, v + n);
#define VREVERSE(v) reverse(v.begin(), v.end())
#define ll long long
#define print(x) cout << (x) << '\n'
#define pe(x) cout << (x) << " "
#define DEBUG(x) cout << #x << ": " << x << endl
#define lb(v, n) lower_bound(v.begin(), v.end(), (n))
#define ub(v, n) upper_bound(v.begin(), v.end(), (n))
#define int long long
// #define double long double
#define all(x) (x).begin(), (x).end()
#define print_space(v)                                                         \
  REP(i, v.size()) cout << v[i] << " \n"[i == (int)v.size() - 1]
template <typename T1, typename T2> inline void chmin(T1 &a, T2 b) {
  if (a > b)
    a = b;
}
template <typename T1, typename T2> inline void chmax(T1 &a, T2 b) {
  if (a < b)
    a = b;
}
typedef pair<int, int> pii;
typedef pair<long long, long long> pll;
std::random_device rd;
std::mt19937 mt(rd());
constexpr ll MOD = 1e9 + 7;
constexpr int MAX = 500050;
const double pi = acos(-1);
constexpr double EPS = 1e-8;
constexpr ll LINF = 1e18 + 1;
constexpr int INF = 1e9 + 1;
// int dx[4] = { 0,0,-1,1 }, dy[4] = { 1,-1,0,0 };

template <typename T> struct SegmentTree {
  int n;
  T unit;
  vector<T> dat;
  function<T(T, T)> func;
  SegmentTree(const int N, T _unit, function<T(T, T)> _func)
      : unit(_unit), func(_func) {
    n = 1;
    // 簡単のため、要素数を2のべき乗に
    while (n < N)
      n *= 2;
    dat.assign(2 * n, unit);
  }

  void update(int k, T a) {
    k += n - 1; // 葉の節点
    dat[k] = a;
    // 上りながら更新
    while (k > 0) {
      k = (k - 1) / 2;
      dat[k] = func(dat[k * 2 + 1], dat[k * 2 + 2]);
    }
  }
  T _query(int a, int b, int k, int l, int r) {
    //[a,b)と[l,r)が交差していなければ、funcに影響を与えない値を返す
    if (r <= a || b <= l)
      return unit;
    //[a,b)が[l,r)を完全に含んでいれば、この節点の値
    if (a <= l && r <= b)
      return dat[k];
    else {
      T vl = _query(a, b, k * 2 + 1, l, (l + r) / 2);
      T vr = _query(a, b, k * 2 + 2, (l + r) / 2, r);
      return func(vl, vr);
    }
  }
  //[a,b)
  T query(int a, int b) { return _query(a, b, 0, 0, n); }
};
// auto f = [](int a, int b) {return a + b; };
// SegmentTree<int>seg(N,0,f);

int las[500020];
void solve() {
  int N, Q;
  cin >> N >> Q;
  vector<int> A(N);
  REP(i, N) cin >> A[i];
  vector<int> L(Q), R(Q);
  vector<pair<pii, int>> v;
  REP(i, Q) {
    cin >> L[i] >> R[i];
    L[i]--, R[i]--;
    v.push_back({{R[i], L[i]}, i});
  }
  REP(i, N + 1) { las[i] = -1; }
  VSORT(v);
  vector<int> ids;
  REP(i, Q) ids.push_back(v[i].second);
  auto f = [](int a, int b) { return a + b; };
  SegmentTree<int> seg(N + 1, 0, f);
  int idx = 0;
  vector<int> ans(Q);
  REP(r, N) {
    // DEBUG(r);
    int pos = las[A[r]];
    if (pos != -1) {
      seg.update(pos, seg.query(pos, pos + 1) - 1);
    }
    las[A[r]] = r;
    int id = ids[idx];
    seg.update(r, seg.query(r, r + 1) + 1);
    while (idx < Q && R[id] == r) {
      // DEBUG(idx);
      // DEBUG(id);
      int l = L[id];
      ans[id] = seg.query(l, r + 1);
      idx++;
      if (idx == Q)
        break;
      id = ids[idx];
    }
  }
  REP(i, Q) print(ans[i]);
}

signed main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  // int q;
  // cin >> q;
  // while (q--)
  solve();
}