Problem p02549 (C++) — buggy submission, verdict: Time Limit Exceeded

// include
//------------------------------------------
#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <chrono>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <locale>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <regex>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

using namespace std;

// typedef
//------------------------------------------
typedef long long LL;
typedef vector<int> VI;
typedef vector<bool> VB;
typedef vector<char> VC;
typedef vector<double> VD;
typedef vector<string> VS;
typedef vector<LL> VLL;
typedef vector<VI> VVI;
typedef vector<VB> VVB;
typedef vector<VS> VVS;
typedef vector<VLL> VVLL;
typedef vector<VVI> VVVI;
typedef vector<VVLL> VVVLL;
typedef pair<int, int> PII;
typedef pair<LL, LL> PLL;
typedef pair<int, string> PIS;
typedef pair<string, int> PSI;
typedef pair<string, string> PSS;
typedef vector<PII> VPII;
typedef vector<PLL> VPLL;
typedef vector<VPII> VVPII;
typedef vector<VPLL> VVPLL;
typedef vector<VS> VVS;
typedef map<int, int> MII;
typedef map<LL, LL> MLL;
typedef map<string, int> MSI;
typedef map<int, string> MIS;

// container util
//------------------------------------------

typedef int pInt[4];
#define ALL(a) (a).begin(), (a).end()
#define SZ(a) int((a).size())
#define EACH(i, arr)                                                           \\
  for (typeof((arr).begin()) i = (arr).begin(); i != (arr).end(); ++i)
#define EXIST(str, e) ((str).find(e) != (str).end())
#define COUNT(arr, v) count((arr).begin(), (arr).end(), v)
#define SEARCH(v, w) search((v).begin(), (v).end(), (w).begin(), (w).end())
#define SORT(c) sort((c).begin(), (c).end())
#define RSORT(c) sort((c).rbegin(), (c).rend())
#define REVERSE(c) reverse((c).begin(), (c).end())
#define ROTATE_LEFT(arr, c)                                                    \\
  rotate((arr).begin(), (arr).begin() + (c), (arr).end())
#define ROTATE_RIGHT(arr, c)                                                   \\
  rotate((arr).rbegin(), (arr).rbegin() + (c), (arr).rend())
#define SUMI(arr) accumulate((arr).begin(), (arr).end(), 0)
#define SUMD(arr) accumulate((arr).begin(), (arr).end(), 0.)
#define SUMLL(arr) accumulate((arr).begin(), (arr).end(), 0LL)
#define MULD(arr)                                                              \\
  accumulate((arr).begin(), (arr).end(), 1., multiplies<double>())
#define UB(arr, n) upper_bound((arr).begin(), (arr).end(), n)
#define LB(arr, n) lower_bound((arr).begin(), (arr).end(), n)
#define PB push_back
#define MP make_pair
#define ft first
#define sd second

// input output
//------------------------------------------
#define GL(s) getline(cin, (s))
#define INIT()                                                                 \\
  std::ios::sync_with_stdio(false);                                            \\
  std::cin.tie(0)
#define OUT(d) std::cout << (d)
#define OUT_L(d) std::cout << (d) << endl
#define FOUT(n, data) std::cout << std::fixed << std::setprecision(n) << (data)
#define FOUT_L(n, data)                                                        \\
  std::cout << std::fixed << std::setprecision(n) << (data) << "\\n"
#define EL() printf("\\n")
#define SHOW_VECTOR(v)                                                         \\
  {                                                                            \\
    std::cerr << #v << "\\t:";                                                  \\
    for (const auto &xxx : v) {                                                \\
      std::cerr << xxx << " ";                                                 \\
    }                                                                          \\
    std::cerr << "\\n";                                                         \\
  }
#define SHOW_MAP(v)                                                            \\
  {                                                                            \\
    std::cerr << #v << endl;                                                   \\
    for (const auto &xxx : v) {                                                \\
      std::cerr << xxx.first << " " << xxx.second << "\\n";                     \\
    }                                                                          \\
  }
#define Yes() printf("Yes\\n")
#define No() printf("No\\n")
#define YES() printf("YES\\n")
#define NO() printf("NO\\n")
#define Yay() printf("Yay!\\n")
#define Nnn() printf(":(\\n")
#define CE(x, y) ((x + y - 1) / (y))

template <typename T1, typename T2>
istream &operator>>(istream &in, pair<T1, T2> &p) {
  in >> p.first >> p.second;
  return in;
}

template <typename T> istream &operator>>(istream &in, vector<T> &v) {
  for (auto &x : v)
    in >> x;
  return in;
}

template <typename T1, typename T2>
ostream &operator<<(ostream &out, const std::pair<T1, T2> &p) {
  out << "[" << p.first << ", " << p.second << "]"
      << "\\n";
  return out;
}

template <class T1, class T2> inline bool chmin(T1 &a, T2 b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}

template <class T1, class T2> inline bool chmax(T1 &a, T2 b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}

// repetition
//------------------------------------------
#define FOR(i, a, b) for (int i = (a); i < (b); ++i)
#define RFOR(i, a, b) for (int i = (b)-1; i >= (a); --i)
#define REP(i, n) FOR(i, 0, n)
#define RREP(i, n) for (int i = n - 1; i >= 0; i--)
#define FORLL(i, a, b) for (LL i = LL(a); i < LL(b); ++i)
#define RFORLL(i, a, b) for (LL i = LL(b) - 1; i >= LL(a); --i)
#define REPLL(i, n) for (LL i = 0; i < LL(n); ++i)
#define RREPLL(i, n) for (LL i = LL(n) - 1; i >= 0; --i)
#define FOREACH(x, arr) for (auto &(x) : (arr))

// Option + Control + K  Terminal
// Command + Control + K    Run
// Command + b   EOF
// #include "atcoder/all"

//------------------------------------------
//------------------------------------------

constexpr LL mod = 998244353;

template <int_fast64_t Modulas = 1000000007ul> class ModInt {
  using u64 = int_fast64_t;

public:
  u64 x;

  constexpr ModInt() : x(0) {}
  constexpr ModInt(int_fast64_t v) : x((v % Modulas + Modulas) % Modulas) {}
  constexpr ModInt operator+(const ModInt rhs) const noexcept {
    return ModInt(*this) += rhs;
  }
  constexpr ModInt operator-(const ModInt rhs) const noexcept {
    return ModInt(*this) -= rhs;
  }
  constexpr ModInt operator*(const ModInt rhs) const noexcept {
    return ModInt(*this) *= rhs;
  }
  constexpr ModInt operator/(const ModInt rhs) const noexcept {
    return ModInt(*this) /= rhs;
  }
  constexpr ModInt operator/(const long long rhs) const noexcept {
    return ModInt(*this) /= rhs;
  }
  constexpr ModInt operator+=(const ModInt rhs) noexcept {
    x += rhs.x;
    if (x >= Modulas)
      x -= Modulas;
    return *this;
  }
  constexpr ModInt operator+=(const long long rhs) noexcept {
    auto hs = ModInt<Modulas>(rhs);
    (*this) += hs;
    return *this;
  }
  constexpr ModInt operator-=(const ModInt rhs) noexcept {
    if (x < rhs.x)
      x += Modulas;
    x -= rhs.x;
    return *this;
  }
  constexpr ModInt operator-=(const long long rhs) noexcept {
    auto hs = ModInt<Modulas>(rhs);
    (*this) -= hs;
    return *this;
  }
  constexpr ModInt operator*=(const ModInt rhs) noexcept {
    x = x * rhs.x % Modulas;
    return *this;
  }
  constexpr ModInt operator*=(const long long rhs) noexcept {
    auto hs = ModInt<Modulas>(rhs);
    (*this) *= hs;
    return *this;
  }
  constexpr ModInt &operator/=(ModInt rhs) noexcept {
    u64 exp = Modulas - 2;
    while (exp > 0) {
      if (exp & 1ul)
        *this *= rhs;
      rhs *= rhs;
      exp >>= 1ul;
    }
    return *this;
  }
  constexpr ModInt &operator/=(long long rhs) noexcept {
    auto hs = ModInt<Modulas>(rhs);
    (*this) /= hs;
    return *this;
  }

  constexpr ModInt &operator++() noexcept {
    x++;
    if (x >= Modulas)
      x -= Modulas;
    return *this;
  }
  constexpr ModInt &operator--() noexcept {
    if (x == 0)
      x += Modulas;
    x--;
    return *this;
  }
  constexpr bool operator<(const ModInt rhs) const noexcept {
    return x < rhs.x;
  }
  constexpr bool operator==(const ModInt rhs) const noexcept {
    return this->x == rhs.x;
  }
  constexpr bool operator!=(const ModInt rhs) const noexcept {
    return !(*this == rhs);
  }
  friend istream &operator>>(istream &in, ModInt &m) {
    in >> m.x;
    if (m.x < 0)
      m.x += Modulas;
    m.x %= Modulas;
    return in;
  }
  friend ostream &operator<<(ostream &out, const ModInt &p) {
    out << p.x;
    return out;
  }
  constexpr ModInt pow(u64 p) const {
    ModInt ret(1);
    ModInt mul(x);
    while (p > 0) {
      if (p & 1ul)
        ret *= mul;
      mul *= mul;
      p >>= 1ul;
    }
    return ret;
  }
  constexpr ModInt operator~() const noexcept {
    u64 exp = Modulas - 2;
    return pow(exp);
  }

  constexpr static ModInt arith_sum(ModInt<Modulas> a, ModInt<Modulas> d,
                                    ModInt<Modulas> n) noexcept {
    return (a * ModInt<Modulas>(2) + (n - 1) * d) * n / ModInt<Modulas>(2);
  }
};

int main() {

  typedef ModInt<mod> MI;

  LL N, K;
  cin >> N >> K;

  VLL L(K), R(K);
  REP(i, K) cin >> L[i] >> R[i];

  vector<MI> dp(N, 0);
  vector<MI> sum(N, 0);
  dp[0] = 1;
  sum[0] = 1;

  for (int i = 1; i < N; i++) {
    REP(k, K) {
      // [l[i], r[i]]
      int l = i - R[k];
      int r = i - L[k];
      if (r < 0)
        continue;
      l = max(l, 0);
      r = max(r, 0);
      dp[i] += (sum[r] - ((l - 1 == -1) ? 0 : sum[l - 1]));
    }
    sum[i] += dp[i] + sum[i - 1];
  }

  cout << dp.back() << endl;

  return 0;
}


Error: TLE

Fixed submission:

// include
//------------------------------------------
#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <chrono>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <locale>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <regex>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

using namespace std;

// typedef
//------------------------------------------
typedef long long LL;
typedef vector<int> VI;
typedef vector<bool> VB;
typedef vector<char> VC;
typedef vector<double> VD;
typedef vector<string> VS;
typedef vector<LL> VLL;
typedef vector<VI> VVI;
typedef vector<VB> VVB;
typedef vector<VS> VVS;
typedef vector<VLL> VVLL;
typedef vector<VVI> VVVI;
typedef vector<VVLL> VVVLL;
typedef pair<int, int> PII;
typedef pair<LL, LL> PLL;
typedef pair<int, string> PIS;
typedef pair<string, int> PSI;
typedef pair<string, string> PSS;
typedef vector<PII> VPII;
typedef vector<PLL> VPLL;
typedef vector<VPII> VVPII;
typedef vector<VPLL> VVPLL;
typedef vector<VS> VVS;
typedef map<int, int> MII;
typedef map<LL, LL> MLL;
typedef map<string, int> MSI;
typedef map<int, string> MIS;

// container util
//------------------------------------------

typedef int pInt[4];
#define ALL(a) (a).begin(), (a).end()
#define SZ(a) int((a).size())
#define EACH(i, arr)                                                           \\
  for (typeof((arr).begin()) i = (arr).begin(); i != (arr).end(); ++i)
#define EXIST(str, e) ((str).find(e) != (str).end())
#define COUNT(arr, v) count((arr).begin(), (arr).end(), v)
#define SEARCH(v, w) search((v).begin(), (v).end(), (w).begin(), (w).end())
#define SORT(c) sort((c).begin(), (c).end())
#define RSORT(c) sort((c).rbegin(), (c).rend())
#define REVERSE(c) reverse((c).begin(), (c).end())
#define ROTATE_LEFT(arr, c)                                                    \\
  rotate((arr).begin(), (arr).begin() + (c), (arr).end())
#define ROTATE_RIGHT(arr, c)                                                   \\
  rotate((arr).rbegin(), (arr).rbegin() + (c), (arr).rend())
#define SUMI(arr) accumulate((arr).begin(), (arr).end(), 0)
#define SUMD(arr) accumulate((arr).begin(), (arr).end(), 0.)
#define SUMLL(arr) accumulate((arr).begin(), (arr).end(), 0LL)
#define MULD(arr)                                                              \\
  accumulate((arr).begin(), (arr).end(), 1., multiplies<double>())
#define UB(arr, n) upper_bound((arr).begin(), (arr).end(), n)
#define LB(arr, n) lower_bound((arr).begin(), (arr).end(), n)
#define PB push_back
#define MP make_pair
#define ft first
#define sd second

// input output
//------------------------------------------
#define GL(s) getline(cin, (s))
#define INIT()                                                                 \\
  std::ios::sync_with_stdio(false);                                            \\
  std::cin.tie(0)
#define OUT(d) std::cout << (d)
#define OUT_L(d) std::cout << (d) << endl
#define FOUT(n, data) std::cout << std::fixed << std::setprecision(n) << (data)
#define FOUT_L(n, data)                                                        \\
  std::cout << std::fixed << std::setprecision(n) << (data) << "\\n"
#define EL() printf("\\n")
#define SHOW_VECTOR(v)                                                         \\
  {                                                                            \\
    std::cerr << #v << "\\t:";                                                  \\
    for (const auto &xxx : v) {                                                \\
      std::cerr << xxx << " ";                                                 \\
    }                                                                          \\
    std::cerr << "\\n";                                                         \\
  }
#define SHOW_MAP(v)                                                            \\
  {                                                                            \\
    std::cerr << #v << endl;                                                   \\
    for (const auto &xxx : v) {                                                \\
      std::cerr << xxx.first << " " << xxx.second << "\\n";                     \\
    }                                                                          \\
  }
#define Yes() printf("Yes\\n")
#define No() printf("No\\n")
#define YES() printf("YES\\n")
#define NO() printf("NO\\n")
#define Yay() printf("Yay!\\n")
#define Nnn() printf(":(\\n")
#define CE(x, y) ((x + y - 1) / (y))

template <typename T1, typename T2>
istream &operator>>(istream &in, pair<T1, T2> &p) {
  in >> p.first >> p.second;
  return in;
}

template <typename T> istream &operator>>(istream &in, vector<T> &v) {
  for (auto &x : v)
    in >> x;
  return in;
}

template <typename T1, typename T2>
ostream &operator<<(ostream &out, const std::pair<T1, T2> &p) {
  out << "[" << p.first << ", " << p.second << "]"
      << "\\n";
  return out;
}

template <class T1, class T2> inline bool chmin(T1 &a, T2 b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}

template <class T1, class T2> inline bool chmax(T1 &a, T2 b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}

// repetition
//------------------------------------------
#define FOR(i, a, b) for (int i = (a); i < (b); ++i)
#define RFOR(i, a, b) for (int i = (b)-1; i >= (a); --i)
#define REP(i, n) FOR(i, 0, n)
#define RREP(i, n) for (int i = n - 1; i >= 0; i--)
#define FORLL(i, a, b) for (LL i = LL(a); i < LL(b); ++i)
#define RFORLL(i, a, b) for (LL i = LL(b) - 1; i >= LL(a); --i)
#define REPLL(i, n) for (LL i = 0; i < LL(n); ++i)
#define RREPLL(i, n) for (LL i = LL(n) - 1; i >= 0; --i)
#define FOREACH(x, arr) for (auto &(x) : (arr))

// Option + Control + K  Terminal
// Command + Control + K    Run
// Command + b   EOF
// #include "atcoder/all"

//------------------------------------------
//------------------------------------------

template <int_fast64_t Modulas = 1000000007ul> class ModInt {
  using u64 = int_fast64_t;

public:
  u64 x;

  constexpr ModInt() : x(0) {}
  constexpr ModInt(int_fast64_t v) : x((v % Modulas + Modulas) % Modulas) {}
  constexpr ModInt operator+(const ModInt rhs) const noexcept {
    return ModInt(*this) += rhs;
  }
  constexpr ModInt operator-(const ModInt rhs) const noexcept {
    return ModInt(*this) -= rhs;
  }
  constexpr ModInt operator*(const ModInt rhs) const noexcept {
    return ModInt(*this) *= rhs;
  }
  constexpr ModInt operator/(const ModInt rhs) const noexcept {
    return ModInt(*this) /= rhs;
  }
  constexpr ModInt operator/(const long long rhs) const noexcept {
    return ModInt(*this) /= rhs;
  }
  constexpr ModInt operator+=(const ModInt rhs) noexcept {
    x += rhs.x;
    if (x >= Modulas)
      x -= Modulas;
    return *this;
  }
  constexpr ModInt operator+=(const long long rhs) noexcept {
    auto hs = ModInt<Modulas>(rhs);
    (*this) += hs;
    return *this;
  }
  constexpr ModInt operator-=(const ModInt rhs) noexcept {
    if (x < rhs.x)
      x += Modulas;
    x -= rhs.x;
    return *this;
  }
  constexpr ModInt operator-=(const long long rhs) noexcept {
    auto hs = ModInt<Modulas>(rhs);
    (*this) -= hs;
    return *this;
  }
  constexpr ModInt operator*=(const ModInt rhs) noexcept {
    x = x * rhs.x % Modulas;
    return *this;
  }
  constexpr ModInt operator*=(const long long rhs) noexcept {
    auto hs = ModInt<Modulas>(rhs);
    (*this) *= hs;
    return *this;
  }
  constexpr ModInt &operator/=(ModInt rhs) noexcept {
    u64 exp = Modulas - 2;
    while (exp > 0) {
      if (exp & 1ul)
        *this *= rhs;
      rhs *= rhs;
      exp >>= 1ul;
    }
    return *this;
  }
  constexpr ModInt &operator/=(long long rhs) noexcept {
    auto hs = ModInt<Modulas>(rhs);
    (*this) /= hs;
    return *this;
  }

  constexpr ModInt &operator++() noexcept {
    x++;
    if (x >= Modulas)
      x -= Modulas;
    return *this;
  }
  constexpr ModInt &operator--() noexcept {
    if (x == 0)
      x += Modulas;
    x--;
    return *this;
  }
  constexpr bool operator<(const ModInt rhs) const noexcept {
    return x < rhs.x;
  }
  constexpr bool operator==(const ModInt rhs) const noexcept {
    return this->x == rhs.x;
  }
  constexpr bool operator!=(const ModInt rhs) const noexcept {
    return !(*this == rhs);
  }
  friend istream &operator>>(istream &in, ModInt &m) {
    in >> m.x;
    if (m.x < 0)
      m.x += Modulas;
    m.x %= Modulas;
    return in;
  }
  friend ostream &operator<<(ostream &out, const ModInt &p) {
    out << p.x;
    return out;
  }
  constexpr ModInt pow(u64 p) const {
    ModInt ret(1);
    ModInt mul(x);
    while (p > 0) {
      if (p & 1ul)
        ret *= mul;
      mul *= mul;
      p >>= 1ul;
    }
    return ret;
  }
  constexpr ModInt operator~() const noexcept {
    u64 exp = Modulas - 2;
    return pow(exp);
  }

  constexpr static ModInt arith_sum(ModInt<Modulas> a, ModInt<Modulas> d,
                                    ModInt<Modulas> n) noexcept {
    return (a * ModInt<Modulas>(2) + (n - 1) * d) * n / ModInt<Modulas>(2);
  }
};

constexpr LL mod = 998244353;

template <typename T> struct LazySegmentTree {

private:
  int n;
  T init_v;
  vector<T> node;
  vector<T> lazy;

public:
  LazySegmentTree(vector<T> a, T _init_v) {

    n = 1;
    init_v = _init_v;

    int sz = a.size();
    while (n < sz)
      n *= 2;

    node.resize(2 * n, init_v);
    lazy.resize(2 * n, init_v);

    for (int i = 0; i < sz; i++)
      node[i + n - 1] = a[i];
    for (int i = n - 2; i >= 0; i--)
      node[i] = node[i * 2 + 1] + node[i * 2 + 2];
  }

  void eval(int k, int l, int r) {
    if (lazy[k] != 0) {
      node[k] += lazy[k];
      if (r - l > 1) {
        lazy[k * 2 + 1] += lazy[k] / 2;
        lazy[k * 2 + 2] += lazy[k] / 2;
      }
      lazy[k] = 0;
    }
  }

  void add(int a, int b, T x, int k = 0, int l = 0, int r = -1) {
    if (r < 0)
      r = n;
    eval(k, l, r);
    if (r <= a || b <= l)
      return;
    if (a <= l && r <= b) {
      ModInt<mod> w = (r - l);
      lazy[k] += w * x;
      eval(k, l, r);
    } else {
      add(a, b, x, k * 2 + 1, l, (l + r) / 2);
      add(a, b, x, k * 2 + 2, (l + r) / 2, r);
      node[k] = node[k * 2 + 1] + node[k * 2 + 2];
    }
  }

  T getsum(int a, int b, int k = 0, int l = 0, int r = -1) {
    if (r < 0)
      r = n;
    eval(k, l, r);
    if (r <= a || b <= l)
      return 0;
    if (a <= l && r <= b)
      return node[k];
    T lv = getsum(a, b, k * 2 + 1, l, (l + r) / 2);
    T rv = getsum(a, b, k * 2 + 2, (l + r) / 2, r);
    return lv + rv;
  }
};

int main() {

  LL N, K;
  scanf("%lld %lld", &N, &K);

  VLL L(K), R(K);
  REP(i, K) scanf("%lld %lld", &L[i], &R[i]), R[i]++;

  LazySegmentTree<ModInt<mod>> tree(vector<ModInt<mod>>(N), 0);

  tree.add(0, 1, 1);

  for (int i = 0; i < N - 1; i++) {
    auto now = tree.getsum(i, i + 1);
    for (int k = 0; k < K; k++) {
      LL l = i + L[k];
      if (l >= N)
        continue;
      LL r = min(i + R[k], N);
      tree.add(l, r, now);
    }
  }

  printf("%lld", tree.getsum(N - 1, N));

  //    cout << tree.getsum(N - 1, N) << endl;

  return 0;
}