Problem p03013 (C++)

Buggy submission (status: Runtime Error):
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<ll, ll> P;
typedef pair<int, int> Pi;
typedef vector<ll> Vec;
typedef vector<int> Vi;
typedef vector<string> Vs;
typedef vector<vector<ll>> VV;

#define REP(i, a, b) for (ll i = (a); i < (b); i++)
#define rep(i, n) REP(i, 0, n)
const int INF = 1e9;
const int MOD = 1000000007;
#define Yes(n) cout << ((n) ? "Yes" : "No") << endl;
#define ALL(v) v.begin(), v.end()
#define dbg(x_) cerr << #x_ << ":" << x_ << endl;
#define pb(x) push_back(x)
#define mp(a, b) make_pair(a, b)
#define Each(a, b) for (auto &a : b)
#define REPM(i, mp) for (auto i = mp.begin(); i != mp.end(); ++i)
#define dbgmap(mp)                                                             \
  for (auto i = mp.begin(); i != mp.end(); ++i) {                              \
    cout << i->first << ":" << i->second << endl;                              \
  }
#define sum(v) accumulate(ALL(v), 0)
#define fi first
#define se second

template <typename T1, typename T2>
ostream &operator<<(ostream &s, const pair<T1, T2> &p) {
  return s << "(" << p.first << ", " << p.second << ")";
}

// vector
template <typename T> ostream &operator<<(ostream &s, const vector<T> &v) {
  int len = v.size();
  for (int i = 0; i < len; ++i) {
    s << v[i];
    if (i < len - 1)
      s << "	";
  }
  return s;
}

// 2 dimentional vector
template <typename T>
ostream &operator<<(ostream &s, const vector<vector<T>> &vv) {
  int len = vv.size();
  for (int i = 0; i < len; ++i) {
    s << vv[i] << endl;
  }
  return s;
}

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  ll n, m;
  cin >> n >> m;
  Vec way(n + 1, 0);
  Vec brk(m + 1, 0);
  rep(i, m) {
    ll tmp;
    cin >> tmp;
    brk[tmp] = 1;
  }
  ll ans = 0;

  way[0] = 1;
  if (brk[1] == 1) {
    way[1] = 0;
  } else {
    way[1] = 1;
  }

  REP(i, 2, n + 1) {
    if (brk[i] == 1) {
      way[i] = 0;
    } else {
      way[i] = way[i - 1] + way[i - 2];
      way[i] %= MOD;
    }
  }
  ans = way[n];
  // dbg(way);
  cout << ans << endl;
  return 0;
}


Fixed submission:
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<ll, ll> P;
typedef pair<int, int> Pi;
typedef vector<ll> Vec;
typedef vector<int> Vi;
typedef vector<string> Vs;
typedef vector<vector<ll>> VV;

#define REP(i, a, b) for (ll i = (a); i < (b); i++)
#define rep(i, n) REP(i, 0, n)
const int INF = 1e9;
const int MOD = 1000000007;
#define Yes(n) cout << ((n) ? "Yes" : "No") << endl;
#define ALL(v) v.begin(), v.end()
#define dbg(x_) cerr << #x_ << ":" << x_ << endl;
#define pb(x) push_back(x)
#define mp(a, b) make_pair(a, b)
#define Each(a, b) for (auto &a : b)
#define REPM(i, mp) for (auto i = mp.begin(); i != mp.end(); ++i)
#define dbgmap(mp)                                                             \
  for (auto i = mp.begin(); i != mp.end(); ++i) {                              \
    cout << i->first << ":" << i->second << endl;                              \
  }
#define sum(v) accumulate(ALL(v), 0)
#define fi first
#define se second

template <typename T1, typename T2>
ostream &operator<<(ostream &s, const pair<T1, T2> &p) {
  return s << "(" << p.first << ", " << p.second << ")";
}

// vector
template <typename T> ostream &operator<<(ostream &s, const vector<T> &v) {
  int len = v.size();
  for (int i = 0; i < len; ++i) {
    s << v[i];
    if (i < len - 1)
      s << "	";
  }
  return s;
}

// 2 dimentional vector
template <typename T>
ostream &operator<<(ostream &s, const vector<vector<T>> &vv) {
  int len = vv.size();
  for (int i = 0; i < len; ++i) {
    s << vv[i] << endl;
  }
  return s;
}

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  ll n, m;
  cin >> n >> m;
  Vec way(n + 1, 0);
  Vec brk(100005, 0);
  rep(i, m) {
    ll tmp;
    cin >> tmp;
    brk[tmp] = 1;
  }
  ll ans = 0;

  way[0] = 1;
  if (brk[1] == 1) {
    way[1] = 0;
  } else {
    way[1] = 1;
  }

  REP(i, 2, n + 1) {
    if (brk[i] == 1) {
      way[i] = 0;
    } else {
      way[i] = way[i - 1] + way[i - 2];
      way[i] %= MOD;
    }
  }
  ans = way[n];
  // dbg(way);
  cout << ans << endl;
  return 0;
}