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

#pragma GCC optimize("O3")
#pragma GCC target("avx")
#include "bits/stdc++.h"

using namespace std;
using ll = long long int;

#define all(v) (v).begin(), (v).end()
#define repeat(cnt, l)                                                         \\
  for (typename remove_const<                                                  \\
           typename remove_reference<decltype(l)>::type>::type cnt = {};       \\
       (cnt) < (l); ++(cnt))
#define rrepeat(cnt, l) for (auto cnt = (l)-1; 0 <= (cnt); --(cnt))
#define iterate(cnt, b, e) for (auto cnt = (b); (cnt) != (e); ++(cnt))
#define diterate(cnt, b, e) for (auto cnt = (b); (cnt) != (e); --(cnt))
const long long MD = 1000000007ll;
const long double PI = 3.1415926535897932384626433832795L;
template <typename T1, typename T2>
inline ostream &operator<<(ostream &o, const pair<T1, T2> p) {
  o << '(' << p.first << ':' << p.second << ')';
  return o;
}
template <typename T> inline T &chmax(T &to, const T &val) {
  return to = max(to, val);
}
template <typename T> inline T &chmin(T &to, const T &val) {
  return to = min(to, val);
}
void bye(string s, int code = 0) {
  cout << s << endl;
  exit(code);
}
mt19937_64 randdev(8901016);
template <typename T, typename Random = decltype(randdev),
          typename enable_if<is_integral<T>::value>::type * = nullptr>
inline T rand(T l, T h, Random &rand = randdev) {
  return uniform_int_distribution<T>(l, h)(rand);
}
template <typename T, typename Random = decltype(randdev),
          typename enable_if<is_floating_point<T>::value>::type * = nullptr>
inline T rand(T l, T h, Random &rand = randdev) {
  return uniform_real_distribution<T>(l, h)(rand);
}

template <typename I> struct MyRangeFormat {
  I b, e;
  MyRangeFormat(I _b, I _e) : b(_b), e(_e) {}
};
template <typename I>
static ostream &operator<<(ostream &o, const MyRangeFormat<I> &f) {
  o << "[ ";
  iterate(i, f.b, f.e) o << *i << ' ';
  return o << ']';
}
template <typename I> struct MyMatrixFormat {
  const I &p;
  long long n, m;
  MyMatrixFormat(const I &_p, long long _n, long long _m)
      : p(_p), n(_n), m(_m) {}
};
template <typename I>
static ostream &operator<<(ostream &o, const MyMatrixFormat<I> &f) {
  o << '\\n';
  repeat(i, (f.n)) {
    repeat(j, f.m) o << f.p[i][j] << ' ';
    o << '\\n';
  }
  return o;
}
struct LOG_t {
  ~LOG_t() { cout << endl; }
};
#define LOG (LOG_t(), cout << 'L' << __LINE__ << ": ")
#define FMTA(m, w) (MyRangeFormat<decltype(m + 0)>(m, m + w))
#define FMTR(b, e) (MyRangeFormat<decltype(e)>(b, e))
#define FMTV(v) FMTR(v.begin(), v.end())
#define FMTM(m, h, w) (MyMatrixFormat<decltype(m + 0)>(m, h, w))

#if defined(_WIN32) || defined(_WIN64)
#define getc_x _getc_nolock
#define putc_x _putc_nolock
#elif defined(__GNUC__)
#define getc_x getc_unlocked
#define putc_x putc_unlocked
#else
#define getc_x getc
#define putc_x putc
#endif
class MaiScanner {
  FILE *fp_;
  constexpr bool isvisiblechar(char c) noexcept {
    return (0x21 <= (c) && (c) <= 0x7E);
  }

public:
  inline MaiScanner(FILE *fp) : fp_(fp) {}
  template <typename T> void input_integer(T &var) noexcept {
    var = 0;
    T sign = 1;
    int cc = getc_x(fp_);
    for (; cc < '0' || '9' < cc; cc = getc_x(fp_))
      if (cc == '-')
        sign = -1;
    for (; '0' <= cc && cc <= '9'; cc = getc_x(fp_))
      var = (var << 3) + (var << 1) + cc - '0';
    var = var * sign;
  }
  inline int c() noexcept { return getc_x(fp_); }
  template <typename T, typename enable_if<is_integral<T>::value,
                                           nullptr_t>::type = nullptr>
  inline MaiScanner &operator>>(T &var) noexcept {
    input_integer<T>(var);
    return *this;
  }
  inline MaiScanner &operator>>(string &var) {
    int cc = getc_x(fp_);
    for (; !isvisiblechar(cc); cc = getc_x(fp_))
      ;
    for (; isvisiblechar(cc); cc = getc_x(fp_))
      var.push_back(cc);
    return *this;
  }
  template <typename IT> inline void in(IT begin, IT end) {
    for (auto it = begin; it != end; ++it)
      *this >> *it;
  }
};
class MaiPrinter {
  FILE *fp_;

public:
  inline MaiPrinter(FILE *fp) : fp_(fp) {}
  template <typename T> void output_integer(T var) noexcept {
    if (var == 0) {
      putc_x('0', fp_);
      return;
    }
    if (var < 0)
      putc_x('-', fp_), var = -var;
    char stack[32];
    int stack_p = 0;
    while (var)
      stack[stack_p++] = '0' + (var % 10), var /= 10;
    while (stack_p)
      putc_x(stack[--stack_p], fp_);
  }
  inline MaiPrinter &operator<<(char c) noexcept {
    putc_x(c, fp_);
    return *this;
  }
  template <typename T, typename enable_if<is_integral<T>::value,
                                           nullptr_t>::type = nullptr>
  inline MaiPrinter &operator<<(T var) noexcept {
    output_integer<T>(var);
    return *this;
  }
  inline MaiPrinter &operator<<(char *str_p) noexcept {
    while (*str_p)
      putc_x(*(str_p++), fp_);
    return *this;
  }
  inline MaiPrinter &operator<<(const string &str) {
    const char *p = str.c_str();
    const char *l = p + str.size();
    while (p < l)
      putc_x(*p++, fp_);
    return *this;
  }
  template <typename IT> void join(IT begin, IT end, char sep = ' ') {
    for (bool b = 0; begin != end; ++begin, b = 1)
      b ? *this << sep << *begin : *this << *begin;
  }
};
MaiScanner scanner(stdin);
MaiPrinter printer(stdout);

template <typename C = std::chrono::milliseconds> class Timer {
  std::chrono::system_clock::time_point tp_;

public:
  static inline auto now() { return std::chrono::system_clock::now(); }
  inline void tic() { tp_ = now(); }
  inline auto toc() const {
    return std::chrono::duration_cast<C>(now() - tp_).count();
  }
  inline Timer() : tp_(now()) {}
};
inline std::ostream &operator<<(std::ostream &o, const Timer<> &t) {
  return o << (long long)t.toc();
}

//

int C[500010];
int results[500010];

//

int que[500010];
int que_cnt = 0;

inline void add(int i) {
  // LOG << "ADD" << i;
  int c = C[i];
  if (que[c] == 0) {
    que_cnt += 1;
  }
  que[c] += 1;
}
inline void del(int i) {
  // LOG << "DEL" << i;
  int c = C[i];
  if (que[c] == 1) {
    que_cnt -= 1;
  }
  que[c] -= 1;
}

//

// BEGIN すぬけ
// https://snuke.hatenablog.com/entry/2016/07/01/000000

int n; // 数列の長さ
int q; // クエリ数
// vector<int> l, r; // クエリの[l,r)
vector<array<int, 2>> LR;
/* 入力 */

void snuke() {
  // ソート
  int sq = sqrt(n);
  vector<int> qi(q);
  for (int i = 0; i < q; ++i)
    qi[i] = i;
  sort(qi.begin(), qi.end(),
       [&](int i, int j) { // クエリの順番をpair(l/sq,r)でソート
         if (LR[i][0] / sq != LR[j][0] / sq)
           return LR[i][0] < LR[j][0];
         return LR[i][1] < LR[j][1];
       });

  // クエリの処理
  // add(i)は追加操作、del(i)は削除操作
  int nl = 0, nr = 0; // [nl,nr)
  for (int i : qi) {
    // LOG << i;
    while (nl > LR[i][0])
      --nl, add(nl);
    while (nr < LR[i][1])
      add(nr), ++nr;
    while (nl < LR[i][0])
      del(nl), ++nl;
    while (nr > LR[i][1])
      --nr, del(nr);
    /* クエリの結果計算 */
    results[i] = que_cnt;
    // LOG << i << "->" << que_cnt;
  }
}

// END すぬけ

void gen() {
  repeat(i, n) { C[i] = rand<int>(1, n); }
  repeat(i, q) {
    int a, b;
    a = rand(1, n);
    b = rand(1, n);
    if (a > b)
      swap(a, b);
    // l[i] = a;
    // r[i] = b;
    LR[i] = {a, b};
  }
}

int main() {
  scanner >> n >> q;
  LR.resize(q);

  scanner.in(C, C + n);

  repeat(i, q) {
    int u, v;
    scanner >> u >> v;
    --u;
    LR[i] = {u, v};
  }
  // gen(); // !!!!!!!!!!!!!!

  snuke(); // すぬけソート

  repeat(i, q) { printer << results[i] << '\\n'; }

  return 0;
}


Error: TLE

Fixed submission:

#pragma GCC optimize("O3")
#include "bits/stdc++.h"

using namespace std;
using ll = long long int;

#define all(v) (v).begin(), (v).end()
#define repeat(cnt, l)                                                         \\
  for (typename remove_const<                                                  \\
           typename remove_reference<decltype(l)>::type>::type cnt = {};       \\
       (cnt) < (l); ++(cnt))
#define rrepeat(cnt, l) for (auto cnt = (l)-1; 0 <= (cnt); --(cnt))
#define iterate(cnt, b, e) for (auto cnt = (b); (cnt) != (e); ++(cnt))
#define diterate(cnt, b, e) for (auto cnt = (b); (cnt) != (e); --(cnt))
const long long MD = 1000000007ll;
const long double PI = 3.1415926535897932384626433832795L;
template <typename T1, typename T2>
inline ostream &operator<<(ostream &o, const pair<T1, T2> p) {
  o << '(' << p.first << ':' << p.second << ')';
  return o;
}
template <typename T> inline T &chmax(T &to, const T &val) {
  return to = max(to, val);
}
template <typename T> inline T &chmin(T &to, const T &val) {
  return to = min(to, val);
}
void bye(string s, int code = 0) {
  cout << s << endl;
  exit(code);
}
mt19937_64 randdev(8901016);
template <typename T, typename Random = decltype(randdev),
          typename enable_if<is_integral<T>::value>::type * = nullptr>
inline T rand(T l, T h, Random &rand = randdev) {
  return uniform_int_distribution<T>(l, h)(rand);
}
template <typename T, typename Random = decltype(randdev),
          typename enable_if<is_floating_point<T>::value>::type * = nullptr>
inline T rand(T l, T h, Random &rand = randdev) {
  return uniform_real_distribution<T>(l, h)(rand);
}

template <typename I> struct MyRangeFormat {
  I b, e;
  MyRangeFormat(I _b, I _e) : b(_b), e(_e) {}
};
template <typename I>
static ostream &operator<<(ostream &o, const MyRangeFormat<I> &f) {
  o << "[ ";
  iterate(i, f.b, f.e) o << *i << ' ';
  return o << ']';
}
template <typename I> struct MyMatrixFormat {
  const I &p;
  long long n, m;
  MyMatrixFormat(const I &_p, long long _n, long long _m)
      : p(_p), n(_n), m(_m) {}
};
template <typename I>
static ostream &operator<<(ostream &o, const MyMatrixFormat<I> &f) {
  o << '\\n';
  repeat(i, (f.n)) {
    repeat(j, f.m) o << f.p[i][j] << ' ';
    o << '\\n';
  }
  return o;
}
struct LOG_t {
  ~LOG_t() { cout << endl; }
};
#define LOG (LOG_t(), cout << 'L' << __LINE__ << ": ")
#define FMTA(m, w) (MyRangeFormat<decltype(m + 0)>(m, m + w))
#define FMTR(b, e) (MyRangeFormat<decltype(e)>(b, e))
#define FMTV(v) FMTR(v.begin(), v.end())
#define FMTM(m, h, w) (MyMatrixFormat<decltype(m + 0)>(m, h, w))

#if defined(_WIN32) || defined(_WIN64)
#define getc_x _getc_nolock
#define putc_x _putc_nolock
#elif defined(__GNUC__)
#define getc_x getc_unlocked
#define putc_x putc_unlocked
#else
#define getc_x getc
#define putc_x putc
#endif
class MaiScanner {
  FILE *fp_;
  constexpr bool isvisiblechar(char c) noexcept {
    return (0x21 <= (c) && (c) <= 0x7E);
  }

public:
  inline MaiScanner(FILE *fp) : fp_(fp) {}
  template <typename T> void input_integer(T &var) noexcept {
    var = 0;
    T sign = 1;
    int cc = getc_x(fp_);
    for (; cc < '0' || '9' < cc; cc = getc_x(fp_))
      if (cc == '-')
        sign = -1;
    for (; '0' <= cc && cc <= '9'; cc = getc_x(fp_))
      var = (var << 3) + (var << 1) + cc - '0';
    var = var * sign;
  }
  inline int c() noexcept { return getc_x(fp_); }
  template <typename T, typename enable_if<is_integral<T>::value,
                                           nullptr_t>::type = nullptr>
  inline MaiScanner &operator>>(T &var) noexcept {
    input_integer<T>(var);
    return *this;
  }
  inline MaiScanner &operator>>(string &var) {
    int cc = getc_x(fp_);
    for (; !isvisiblechar(cc); cc = getc_x(fp_))
      ;
    for (; isvisiblechar(cc); cc = getc_x(fp_))
      var.push_back(cc);
    return *this;
  }
  template <typename IT> inline void in(IT begin, IT end) {
    for (auto it = begin; it != end; ++it)
      *this >> *it;
  }
};
class MaiPrinter {
  FILE *fp_;

public:
  inline MaiPrinter(FILE *fp) : fp_(fp) {}
  template <typename T> void output_integer(T var) noexcept {
    if (var == 0) {
      putc_x('0', fp_);
      return;
    }
    if (var < 0)
      putc_x('-', fp_), var = -var;
    char stack[32];
    int stack_p = 0;
    while (var)
      stack[stack_p++] = '0' + (var % 10), var /= 10;
    while (stack_p)
      putc_x(stack[--stack_p], fp_);
  }
  inline MaiPrinter &operator<<(char c) noexcept {
    putc_x(c, fp_);
    return *this;
  }
  template <typename T, typename enable_if<is_integral<T>::value,
                                           nullptr_t>::type = nullptr>
  inline MaiPrinter &operator<<(T var) noexcept {
    output_integer<T>(var);
    return *this;
  }
  inline MaiPrinter &operator<<(char *str_p) noexcept {
    while (*str_p)
      putc_x(*(str_p++), fp_);
    return *this;
  }
  inline MaiPrinter &operator<<(const string &str) {
    const char *p = str.c_str();
    const char *l = p + str.size();
    while (p < l)
      putc_x(*p++, fp_);
    return *this;
  }
  template <typename IT> void join(IT begin, IT end, char sep = ' ') {
    for (bool b = 0; begin != end; ++begin, b = 1)
      b ? *this << sep << *begin : *this << *begin;
  }
};
MaiScanner scanner(stdin);
MaiPrinter printer(stdout);

//

int C[500010];
int results[500010];

//

int que[500010];
int que_cnt = 0;

void add(int i) {
  // LOG << "ADD" << i;
  int c = C[i];
  if (que[c] == 0) {
    que_cnt += 1;
  }
  que[c] += 1;
}
void del(int i) {
  // LOG << "DEL" << i;
  int c = C[i];
  if (que[c] == 1) {
    que_cnt -= 1;
  }
  que[c] -= 1;
}

//

// BEGIN すぬけ
// https://snuke.hatenablog.com/entry/2016/07/01/000000

int n; // 数列の長さ
int q; // クエリ数
// vector<int> l, r; // クエリの[l,r)
vector<array<int, 2>> LR;
/* 入力 */

void snuke() {
  // ソート
  int sq = sqrt(n);
  vector<int> qi(q);
  for (int i = 0; i < q; ++i)
    qi[i] = i;
  sort(qi.begin(), qi.end(),
       [&](int i, int j) { // クエリの順番をpair(l/sq,r)でソート
         if (LR[i][0] / sq != LR[j][0] / sq)
           return LR[i][0] < LR[j][0];
         return LR[i][1] < LR[j][1];
       });

  // クエリの処理
  // add(i)は追加操作、del(i)は削除操作
  int nl = 0, nr = 0; // [nl,nr)
  for (int i : qi) {
    // LOG << i;
    while (nl > LR[i][0])
      --nl, add(nl);
    while (nr < LR[i][1])
      add(nr), ++nr;
    while (nl < LR[i][0])
      del(nl), ++nl;
    while (nr > LR[i][1])
      --nr, del(nr);
    /* クエリの結果計算 */
    results[i] = que_cnt;
    // LOG << i << "->" << que_cnt;
  }
}

// END すぬけ

void gen() {
  repeat(i, n) { C[i] = rand<int>(1, 99); }
  repeat(i, q) {
    int a, b;
    a = rand(1, n);
    b = rand(1, n);
    if (a > b)
      swap(a, b);
    // l[i] = a;
    // r[i] = b;
    LR[i] = {a, b};
  }
}

int main() {
  scanner >> n >> q;
  scanner.in(C, C + n);

  // l.resize(q);
  // r.resize(q);
  LR.resize(q);

  repeat(i, q) {
    int u, v;
    scanner >> u >> v;
    --u;
    LR[i] = {u, v};
  }
  // gen(); // !!!!!!!!!!!!!!

  snuke(); // すぬけソート

  repeat(i, q) { printer << results[i] << '\\n'; }

  return 0;
}