Problem p02549 (C++) — buggy submission, verdict: Runtime Error

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/detail/standard_policies.hpp>
#include <ext/pb_ds/tree_policy.hpp>

const double pi = 3.141592653589793238462643383279;
using namespace std;
using namespace __gnu_pbds;
// typedef
//------------------------------------------
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef pair<long long, long long> PLL;
typedef pair<int, PII> TIII;
typedef long long LL;
typedef unsigned long long ULL;
typedef vector<LL> VLL;
typedef vector<VLL> VVLL;

// container util
//------------------------------------------
#define ALL(a) (a).begin(), (a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SQ(a) ((a) * (a))
#define EACH(i, c)                                                             \\
  for (typeof((c).begin()) i = (c).begin(); i != (c).end(); ++i)
#define EXIST(s, e) ((s).find(e) != (s).end())
#define SORT(c) sort((c).begin(), (c).end())

// repetition
//------------------------------------------
#define FOR(i, s, n) for (int i = s; i < (int)n; ++i)
#define REP(i, n) FOR(i, 0, n)
#define MOD 1000000007

#define rep(i, a, b) for (int i = a; i < (b); ++i)
#define trav(a, x) for (auto &a : x)
#define all(x) x.begin(), x.end()
#define sz(x) (int)(x).size()

typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;

#define chmin(x, y) x = min(x, y)
#define chmax(x, y) x = max(x, y)

const long double EPS = 1e-6, PI = acos((long double)-1);

// ここから編集

const int MOD2 = 998244353;
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(7);

  int N, K;
  cin >> N >> K;
  vector<pair<int, int>> p;
  REP(i, K) {
    int l, r;
    cin >> l >> r;
    r++;
    p.push_back({l, r});
  }
  vector<ll> dp(N);
  dp[0] = 1;
  dp[1] = -1;
  for (int i = 0; i < N; i++) {
    if (i > 0)
      dp[i] += dp[i - 1];
    dp[i] %= MOD2;
    for (int j = 0; j < K; j++) {
      int l = p[j].first, r = p[j].second;
      if (i + l < N) {
        dp[i + l] += dp[i];
        dp[i + l] %= MOD2;
      }
      if (i + r < N) {
        dp[i + r] = (dp[i + r] - dp[i] + MOD2) % MOD2;
      }
    }
  }
  cout << dp[N - 1] << endl;

  return 0;
}

Error: 0

Fixed submission:

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/detail/standard_policies.hpp>
#include <ext/pb_ds/tree_policy.hpp>

const double pi = 3.141592653589793238462643383279;
using namespace std;
using namespace __gnu_pbds;
// typedef
//------------------------------------------
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef pair<long long, long long> PLL;
typedef pair<int, PII> TIII;
typedef long long LL;
typedef unsigned long long ULL;
typedef vector<LL> VLL;
typedef vector<VLL> VVLL;

// container util
//------------------------------------------
#define ALL(a) (a).begin(), (a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SQ(a) ((a) * (a))
#define EACH(i, c)                                                             \\
  for (typeof((c).begin()) i = (c).begin(); i != (c).end(); ++i)
#define EXIST(s, e) ((s).find(e) != (s).end())
#define SORT(c) sort((c).begin(), (c).end())

// repetition
//------------------------------------------
#define FOR(i, s, n) for (int i = s; i < (int)n; ++i)
#define REP(i, n) FOR(i, 0, n)
#define MOD 1000000007

#define rep(i, a, b) for (int i = a; i < (b); ++i)
#define trav(a, x) for (auto &a : x)
#define all(x) x.begin(), x.end()
#define sz(x) (int)(x).size()

typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;

#define chmin(x, y) x = min(x, y)
#define chmax(x, y) x = max(x, y)

const long double EPS = 1e-6, PI = acos((long double)-1);

// ここから編集

const int MOD2 = 998244353;
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(7);

  int N, K;
  cin >> N >> K;
  vector<pair<int, int>> p;
  REP(i, K) {
    int l, r;
    cin >> l >> r;
    r++;
    p.push_back({l, r});
  }
  vector<ll> dp(N);
  dp[0] = 1;
  dp[1] = -1;
  for (int i = 0; i < N; i++) {
    if (i > 0)
      dp[i] += dp[i - 1];
    dp[i] %= MOD2;
    for (int j = 0; j < K; j++) {
      int l = p[j].first, r = p[j].second;
      if (i + l < N)
        dp[i + l] += dp[i];
      dp[i + l] %= MOD2;
      if (i + r < N)
        dp[i + r] = (dp[i + r] - dp[i] + MOD2) % MOD2;
      dp[i + r] %= MOD2;
    }
  }
  cout << dp[N - 1] << endl;

  return 0;
}