Problem p02549 (C++)

Buggy submission (status: Runtime Error):
#include <bits/stdc++.h>
using namespace std;
#pragma region atcoder
// #include <atcoder/all>
// using namespace atcoder;
#pragma endregion
#pragma region macros
using ll = long long;
using vi = vector<int>;
using vs = vector<string>;
using vl = vector<ll>;
using vb = vector<bool>;
using vvi = vector<vector<int>>;
using vvl = vector<vector<ll>>;
#define rep(i, n) for (int i = 0; i < n; i++)
#define rrep(i, n) for (int i = n - 1; i >= 0; i--)
#define all(x) (x).begin(), (x).end()
#define sz(x) ((int)(x).size())
#pragma endregion
#pragma region debug for var, v, vv
#define debug(var)                                                             \
  do {                                                                         \
    std::cout << #var << " : ";                                                \
    view(var);                                                                 \
  } while (0)
template <typename T> void view(T e) { std::cout << e << std::endl; }
template <typename T> void view(const std::vector<T> &v) {
  for (const auto &e : v) {
    std::cout << e << " ";
  }
  std::cout << std::endl;
}
template <typename T> void view(const std::vector<std::vector<T>> &vv) {
  cout << endl;
  int cnt = 0;
  for (const auto &v : vv) {
    cout << cnt << "th : ";
    view(v);
    cnt++;
  }
  cout << endl;
}
#pragma endregion

const ll mod = 998244353;
const int inf = 1001001001;
const ll INF = 1001001001001001001;
const int MAX = 2000005;

// using mint = modint998244353;
// These are for segment tree
/*int op(int a, int b){return max(a, b);}
int e(){return -1;}
bool f(int v){ return v < target;}
*/

int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};

template <class T> bool chmax(T &a, const T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T> bool chmin(T &a, const T b) {
  if (b < a) {
    a = b;
    return 1;
  }
  return 0;
}
ll modpow(ll a, ll p) {
  ll ret = 1;
  while (p) {
    if (p & 1) {
      ret = ret * a % mod;
    }
    a = a * a % mod;
    p >>= 1;
  }
  return ret;
}

/*--------------------------------------------------------------------------------------------------------------------------------*/

ll dp[200005];

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int n, k;
  cin >> n >> k;
  vector<int> l(k), r(k);
  for (int i = 0; i < k; i++) {
    cin >> l[i] >> r[i];
  }
  dp[1] = 1;
  for (int i = 1; i <= n; i++) {
    if (i > 2) {
      dp[i] += dp[i - 1];
      dp[i] %= mod;
    }
    for (int j = 0; j < k; j++) {
      dp[i + l[j]] += dp[i];
      dp[i + l[j]] %= mod;
      dp[i + r[j] + 1] += (mod - dp[i]) % mod;
    }
  }
  cout << dp[n] % mod << endl;
}

Fixed submission:
#include <bits/stdc++.h>
using namespace std;
#pragma region atcoder
// #include <atcoder/all>
// using namespace atcoder;
#pragma endregion
#pragma region macros
using ll = long long;
using vi = vector<int>;
using vs = vector<string>;
using vl = vector<ll>;
using vb = vector<bool>;
using vvi = vector<vector<int>>;
using vvl = vector<vector<ll>>;
#define rep(i, n) for (int i = 0; i < n; i++)
#define rrep(i, n) for (int i = n - 1; i >= 0; i--)
#define all(x) (x).begin(), (x).end()
#define sz(x) ((int)(x).size())
#pragma endregion
#pragma region debug for var, v, vv
#define debug(var)                                                             \
  do {                                                                         \
    std::cout << #var << " : ";                                                \
    view(var);                                                                 \
  } while (0)
template <typename T> void view(T e) { std::cout << e << std::endl; }
template <typename T> void view(const std::vector<T> &v) {
  for (const auto &e : v) {
    std::cout << e << " ";
  }
  std::cout << std::endl;
}
template <typename T> void view(const std::vector<std::vector<T>> &vv) {
  cout << endl;
  int cnt = 0;
  for (const auto &v : vv) {
    cout << cnt << "th : ";
    view(v);
    cnt++;
  }
  cout << endl;
}
#pragma endregion

const ll mod = 998244353;
const int inf = 1001001001;
const ll INF = 1001001001001001001;
const int MAX = 2000005;

// using mint = modint998244353;
// These are for segment tree
/*int op(int a, int b){return max(a, b);}
int e(){return -1;}
bool f(int v){ return v < target;}
*/

int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};

template <class T> bool chmax(T &a, const T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T> bool chmin(T &a, const T b) {
  if (b < a) {
    a = b;
    return 1;
  }
  return 0;
}
ll modpow(ll a, ll p) {
  ll ret = 1;
  while (p) {
    if (p & 1) {
      ret = ret * a % mod;
    }
    a = a * a % mod;
    p >>= 1;
  }
  return ret;
}

/*--------------------------------------------------------------------------------------------------------------------------------*/

ll dp[200005];

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int n, k;
  cin >> n >> k;
  vector<int> l(k), r(k);
  for (int i = 0; i < k; i++) {
    cin >> l[i] >> r[i];
  }
  dp[1] = 1;
  for (int i = 1; i <= n; i++) {
    if (i > 2) {
      dp[i] += dp[i - 1];
      dp[i] %= mod;
    }
    for (int j = 0; j < k; j++) {
      if (i + l[j] <= 200004) {
        dp[i + l[j]] += dp[i];
        dp[i + l[j]] %= mod;
      }
      if (i + r[j] <= 200004)
        dp[i + r[j] + 1] += (mod - dp[i]) % mod;
    }
  }
  cout << dp[n] % mod << endl;
}