Problem p01769 (C++)

Buggy submission (status: Runtime Error):
#include <algorithm> // other
#include <bitset>
#include <cassert> // c
#include <complex>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream> // io
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <regex>
#include <set>
#include <sstream>
#include <stack>
#include <vector> // container
using namespace std;

typedef long long ll;
typedef unsigned long long ull;

#define ALL(c) (begin(c)), (end(c))
#define REP(i, n) FOR(i, 0, n)
#define REPr(i, n) FORr(i, 0, n)
#define FOR(i, l, r) for (int i = (int)(l); i < (int)(r); ++i)
#define FORr(i, l, r) for (int i = (int)(r)-1; i >= (int)(l); --i)
#define EACH(it, o) for (auto it = (o).begin(); it != (o).end(); ++it)
#define IN(l, v, r) ((l) <= (v) && (v) < (r))
#define UNIQUE(v) v.erase(unique(ALL(v)), v.end())
// debug
#define DUMP(x) cerr << #x << " = " << (x)
#define LINE() cerr << " (L" << __LINE__ << ")"

class range {
private:
  struct Iter {
    int v;
    int operator*() { return v; }
    bool operator!=(Iter &itr) { return v < itr.v; }
    void operator++() { ++v; }
  };
  Iter i, n;

public:
  range(int n) : i({0}), n({n}) {}
  range(int i, int n) : i({i}), n({n}) {}
  Iter &begin() { return i; }
  Iter &end() { return n; }
};

// input
template <typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p) {
  is >> p.first >> p.second;
  return is;
}
template <typename T1> istream &operator>>(istream &is, tuple<T1> &t) {
  is >> get<0>(t);
  return is;
}
template <typename T1, typename T2>
istream &operator>>(istream &is, tuple<T1, T2> &t) {
  is >> get<0>(t) >> get<1>(t);
  return is;
}
template <typename T1, typename T2, typename T3>
istream &operator>>(istream &is, tuple<T1, T2, T3> &t) {
  is >> get<0>(t) >> get<1>(t) >> get<2>(t);
  return is;
}
template <typename T1, typename T2, typename T3, typename T4>
istream &operator>>(istream &is, tuple<T1, T2, T3, T4> &t) {
  is >> get<0>(t) >> get<1>(t) >> get<2>(t) >> get<3>(t);
  return is;
}
template <typename T1, typename T2, typename T3, typename T4, typename T5>
istream &operator>>(istream &is, const tuple<T1, T2, T3, T4, T5> &t) {
  is >> get<0>(t) >> get<1>(t) >> get<2>(t) >> get<3>(t) >> get<4>(t);
  return is;
}
template <typename T1, typename T2, typename T3, typename T4, typename T5,
          typename T6>
istream &operator>>(istream &is, const tuple<T1, T2, T3, T4, T5, T6> &t) {
  is >> get<0>(t) >> get<1>(t) >> get<2>(t) >> get<3>(t) >> get<4>(t) >>
      get<5>(t);
  return is;
}
template <typename T1, typename T2, typename T3, typename T4, typename T5,
          typename T6, typename T7>
istream &operator>>(istream &is, const tuple<T1, T2, T3, T4, T5, T6, T7> &t) {
  is >> get<0>(t) >> get<1>(t) >> get<2>(t) >> get<3>(t) >> get<4>(t) >>
      get<5>(t) >> get<6>(t);
  return is;
}
template <typename T> istream &operator>>(istream &is, vector<T> &as) {
  REP(i, as.size()) is >> as[i];
  return is;
}

// output
template <typename T> ostream &operator<<(ostream &os, const set<T> &ss) {
  for (auto a : ss) {
    if (a != ss.begin())
      os << " ";
    os << a;
  }
  return os;
}
template <typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) {
  os << p.first << " " << p.second;
  return os;
}
template <typename K, typename V>
ostream &operator<<(ostream &os, const map<K, V> &m) {
  bool isF = true;
  for (auto &p : m) {
    if (!isF)
      os << endl;
    os << p;
    isF = false;
  }
  return os;
}
template <typename T1> ostream &operator<<(ostream &os, const tuple<T1> &t) {
  os << get<0>(t);
  return os;
}
template <typename T1, typename T2>
ostream &operator<<(ostream &os, const tuple<T1, T2> &t) {
  os << get<0>(t) << " " << get<1>(t);
  return os;
}
template <typename T1, typename T2, typename T3>
ostream &operator<<(ostream &os, const tuple<T1, T2, T3> &t) {
  os << get<0>(t) << " " << get<1>(t) << " " << get<2>(t);
  return os;
}
template <typename T1, typename T2, typename T3, typename T4>
ostream &operator<<(ostream &os, const tuple<T1, T2, T3, T4> &t) {
  os << get<0>(t) << " " << get<1>(t) << " " << get<2>(t) << " " << get<3>(t);
  return os;
}
template <typename T1, typename T2, typename T3, typename T4, typename T5>
ostream &operator<<(ostream &os, const tuple<T1, T2, T3, T4, T5> &t) {
  os << get<0>(t) << " " << get<1>(t) << " " << get<2>(t) << " " << get<3>(t)
     << " " << get<4>(t);
  return os;
}
template <typename T1, typename T2, typename T3, typename T4, typename T5,
          typename T6>
ostream &operator<<(ostream &os, const tuple<T1, T2, T3, T4, T5, T6> &t) {
  os << get<0>(t) << " " << get<1>(t) << " " << get<2>(t) << " " << get<3>(t)
     << " " << get<4>(t) << " " << get<5>(t);
  return os;
}
template <typename T1, typename T2, typename T3, typename T4, typename T5,
          typename T6, typename T7>
ostream &operator<<(ostream &os, const tuple<T1, T2, T3, T4, T5, T6, T7> &t) {
  os << get<0>(t) << " " << get<1>(t) << " " << get<2>(t) << " " << get<3>(t)
     << " " << get<4>(t) << " " << get<5>(t) << " " << get<6>(t);
  return os;
}
template <typename T> ostream &operator<<(ostream &os, const vector<T> &as) {
  REP(i, as.size()) {
    if (i != 0)
      os << " ";
    os << as[i];
  }
  return os;
}
template <typename T>
ostream &operator<<(ostream &os, const vector<vector<T>> &as) {
  REP(i, as.size()) {
    if (i != 0)
      os << endl;
    os << as[i];
  }
  return os;
}

// values
template <typename T> T INF() { assert(false); };
template <> int INF<int>() { return 1 << 28; };
template <> ll INF<ll>() { return 1LL << 58; };
template <> double INF<double>() { return 1e16; };
template <> long double INF<long double>() { return 1e16; };

template <class T> T EPS() { assert(false); };
template <> int EPS<int>() { return 1; };
template <> ll EPS<ll>() { return 1LL; };
template <> double EPS<double>() { return 1e-8; };
template <> long double EPS<long double>() { return 1e-8; };

template <typename T, typename U> T pmod(T v, U M) { return (v % M + M) % M; }

int MOD = 1e9 + 7;
class Main {
public:
  vector<vector<int>> dp;
  vector<int> xs, as;

  // i?????????<=l
  int dfs(int i, int l) {
    if (as[i] != 0 && (l - xs[i]) % as[i] != 0)
      return dfs(i, xs[i] + (l - xs[i]) / as[i] * as[i]);
    if (as[i] == 0 && xs[i] < l)
      return dfs(i, xs[i]);
    if (i < 0)
      return 1;
    if (dp[i][l] != -1)
      return dp[i][l];
    ll res = 0;
    if (as[i] != 0 && xs[i] <= l - as[i])
      res = (res + dfs(i, l - as[i])) % MOD;
    if (xs[i] <= l)
      res = (res + dfs(i - 1, l - 1)) % MOD;
    return dp[i][l] = res;
  }
  void run() {
    int N, L;
    cin >> N >> L;
    dp = vector<vector<int>>(N, vector<int>(L + 1, -1));
    xs = vector<int>(N);
    cin >> xs;
    as = vector<int>(N);
    cin >> as;

    cout << dfs(N - 1, xs[N - 1] + (L - 1 - xs[N - 1]) / as[N - 1] * as[N - 1])
         << endl;
  }
};

int main() {
  cout << fixed << setprecision(20);
  cin.tie(0);
  ios::sync_with_stdio(false);
  Main().run();
  return 0;
}

Fixed submission:
#include <algorithm> // other
#include <bitset>
#include <cassert> // c
#include <complex>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream> // io
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <regex>
#include <set>
#include <sstream>
#include <stack>
#include <vector> // container
using namespace std;

typedef long long ll;
typedef unsigned long long ull;

#define ALL(c) (begin(c)), (end(c))
#define REP(i, n) FOR(i, 0, n)
#define REPr(i, n) FORr(i, 0, n)
#define FOR(i, l, r) for (int i = (int)(l); i < (int)(r); ++i)
#define FORr(i, l, r) for (int i = (int)(r)-1; i >= (int)(l); --i)
#define EACH(it, o) for (auto it = (o).begin(); it != (o).end(); ++it)
#define IN(l, v, r) ((l) <= (v) && (v) < (r))
#define UNIQUE(v) v.erase(unique(ALL(v)), v.end())
// debug
#define DUMP(x) cerr << #x << " = " << (x)
#define LINE() cerr << " (L" << __LINE__ << ")"

class range {
private:
  struct Iter {
    int v;
    int operator*() { return v; }
    bool operator!=(Iter &itr) { return v < itr.v; }
    void operator++() { ++v; }
  };
  Iter i, n;

public:
  range(int n) : i({0}), n({n}) {}
  range(int i, int n) : i({i}), n({n}) {}
  Iter &begin() { return i; }
  Iter &end() { return n; }
};

// input
template <typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p) {
  is >> p.first >> p.second;
  return is;
}
template <typename T1> istream &operator>>(istream &is, tuple<T1> &t) {
  is >> get<0>(t);
  return is;
}
template <typename T1, typename T2>
istream &operator>>(istream &is, tuple<T1, T2> &t) {
  is >> get<0>(t) >> get<1>(t);
  return is;
}
template <typename T1, typename T2, typename T3>
istream &operator>>(istream &is, tuple<T1, T2, T3> &t) {
  is >> get<0>(t) >> get<1>(t) >> get<2>(t);
  return is;
}
template <typename T1, typename T2, typename T3, typename T4>
istream &operator>>(istream &is, tuple<T1, T2, T3, T4> &t) {
  is >> get<0>(t) >> get<1>(t) >> get<2>(t) >> get<3>(t);
  return is;
}
template <typename T1, typename T2, typename T3, typename T4, typename T5>
istream &operator>>(istream &is, const tuple<T1, T2, T3, T4, T5> &t) {
  is >> get<0>(t) >> get<1>(t) >> get<2>(t) >> get<3>(t) >> get<4>(t);
  return is;
}
template <typename T1, typename T2, typename T3, typename T4, typename T5,
          typename T6>
istream &operator>>(istream &is, const tuple<T1, T2, T3, T4, T5, T6> &t) {
  is >> get<0>(t) >> get<1>(t) >> get<2>(t) >> get<3>(t) >> get<4>(t) >>
      get<5>(t);
  return is;
}
template <typename T1, typename T2, typename T3, typename T4, typename T5,
          typename T6, typename T7>
istream &operator>>(istream &is, const tuple<T1, T2, T3, T4, T5, T6, T7> &t) {
  is >> get<0>(t) >> get<1>(t) >> get<2>(t) >> get<3>(t) >> get<4>(t) >>
      get<5>(t) >> get<6>(t);
  return is;
}
template <typename T> istream &operator>>(istream &is, vector<T> &as) {
  REP(i, as.size()) is >> as[i];
  return is;
}

// output
template <typename T> ostream &operator<<(ostream &os, const set<T> &ss) {
  for (auto a : ss) {
    if (a != ss.begin())
      os << " ";
    os << a;
  }
  return os;
}
template <typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) {
  os << p.first << " " << p.second;
  return os;
}
template <typename K, typename V>
ostream &operator<<(ostream &os, const map<K, V> &m) {
  bool isF = true;
  for (auto &p : m) {
    if (!isF)
      os << endl;
    os << p;
    isF = false;
  }
  return os;
}
template <typename T1> ostream &operator<<(ostream &os, const tuple<T1> &t) {
  os << get<0>(t);
  return os;
}
template <typename T1, typename T2>
ostream &operator<<(ostream &os, const tuple<T1, T2> &t) {
  os << get<0>(t) << " " << get<1>(t);
  return os;
}
template <typename T1, typename T2, typename T3>
ostream &operator<<(ostream &os, const tuple<T1, T2, T3> &t) {
  os << get<0>(t) << " " << get<1>(t) << " " << get<2>(t);
  return os;
}
template <typename T1, typename T2, typename T3, typename T4>
ostream &operator<<(ostream &os, const tuple<T1, T2, T3, T4> &t) {
  os << get<0>(t) << " " << get<1>(t) << " " << get<2>(t) << " " << get<3>(t);
  return os;
}
template <typename T1, typename T2, typename T3, typename T4, typename T5>
ostream &operator<<(ostream &os, const tuple<T1, T2, T3, T4, T5> &t) {
  os << get<0>(t) << " " << get<1>(t) << " " << get<2>(t) << " " << get<3>(t)
     << " " << get<4>(t);
  return os;
}
template <typename T1, typename T2, typename T3, typename T4, typename T5,
          typename T6>
ostream &operator<<(ostream &os, const tuple<T1, T2, T3, T4, T5, T6> &t) {
  os << get<0>(t) << " " << get<1>(t) << " " << get<2>(t) << " " << get<3>(t)
     << " " << get<4>(t) << " " << get<5>(t);
  return os;
}
template <typename T1, typename T2, typename T3, typename T4, typename T5,
          typename T6, typename T7>
ostream &operator<<(ostream &os, const tuple<T1, T2, T3, T4, T5, T6, T7> &t) {
  os << get<0>(t) << " " << get<1>(t) << " " << get<2>(t) << " " << get<3>(t)
     << " " << get<4>(t) << " " << get<5>(t) << " " << get<6>(t);
  return os;
}
template <typename T> ostream &operator<<(ostream &os, const vector<T> &as) {
  REP(i, as.size()) {
    if (i != 0)
      os << " ";
    os << as[i];
  }
  return os;
}
template <typename T>
ostream &operator<<(ostream &os, const vector<vector<T>> &as) {
  REP(i, as.size()) {
    if (i != 0)
      os << endl;
    os << as[i];
  }
  return os;
}

// values
template <typename T> T INF() { assert(false); };
template <> int INF<int>() { return 1 << 28; };
template <> ll INF<ll>() { return 1LL << 58; };
template <> double INF<double>() { return 1e16; };
template <> long double INF<long double>() { return 1e16; };

template <class T> T EPS() { assert(false); };
template <> int EPS<int>() { return 1; };
template <> ll EPS<ll>() { return 1LL; };
template <> double EPS<double>() { return 1e-8; };
template <> long double EPS<long double>() { return 1e-8; };

template <typename T, typename U> T pmod(T v, U M) { return (v % M + M) % M; }

int MOD = 1e9 + 7;
class Main {
public:
  vector<vector<int>> dp;
  vector<int> xs, as;

  // i?????????<=l
  int dfs(int i, int l) {
    if (as[i] != 0 && (l - xs[i]) % as[i] != 0)
      return dfs(i, xs[i] + (l - xs[i]) / as[i] * as[i]);
    if (as[i] == 0 && xs[i] < l)
      return dfs(i, xs[i]);
    if (i < 0)
      return 1;
    if (dp[i][l] != -1)
      return dp[i][l];
    ll res = 0;
    if (as[i] != 0 && xs[i] <= l - as[i])
      res = (res + dfs(i, l - as[i])) % MOD;
    if (xs[i] <= l)
      res = (res + dfs(i - 1, l - 1)) % MOD;
    return dp[i][l] = res;
  }
  void run() {
    int N, L;
    cin >> N >> L;
    dp = vector<vector<int>>(N, vector<int>(L + 1, -1));
    xs = vector<int>(N);
    cin >> xs;
    as = vector<int>(N);
    cin >> as;
    cout << dfs(N - 1, L - 1) << endl;
  }
};

int main() {
  cout << fixed << setprecision(20);
  cin.tie(0);
  ios::sync_with_stdio(false);
  Main().run();
  return 0;
}