Problem p02589 (C++) — buggy submission, verdict: Runtime Error

#include <bits/stdc++.h>
using namespace std;
struct fast_ios {
  fast_ios() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(20);
  };
} fast_ios_;
#define FOR(i, begin, end) for (int i = (begin); i < (end); i++)
#define REP(i, n) FOR(i, 0, n)
#define IFOR(i, begin, end) for (int i = (end)-1; i >= (begin); i--)
#define IREP(i, n) IFOR(i, 0, n)
#define Sort(v) sort(v.begin(), v.end())
#define Reverse(v) reverse(v.begin(), v.end())
#define all(v) v.begin(), v.end()
#define SZ(v) ((int)v.size())
#define Lower_bound(v, x)                                                      \\
  distance(v.begin(), lower_bound(v.begin(), v.end(), x))
#define Upper_bound(v, x)                                                      \\
  distance(v.begin(), upper_bound(v.begin(), v.end(), x))
#define chmax(a, b) a = max(a, b)
#define chmin(a, b) a = min(a, b)
#define bit(n) (1LL << (n))
#define debug(x) cout << #x << "=" << x << endl;
#define vdebug(v)                                                              \\
  {                                                                            \\
    cout << #v << "=" << endl;                                                 \\
    REP(i_debug, v.size()) { cout << v[i_debug] << ","; }                      \\
    cout << endl;                                                              \\
  }
#define mdebug(m)                                                              \\
  {                                                                            \\
    cout << #m << "=" << endl;                                                 \\
    REP(i_debug, m.size()) {                                                   \\
      REP(j_debug, m[i_debug].size()) { cout << m[i_debug][j_debug] << ","; }  \\
      cout << endl;                                                            \\
    }                                                                          \\
  }
#define pb push_back
#define fi first
#define se second
// #define int long long
// #define INF 1000000000000000000
template <typename T> istream &operator>>(istream &is, vector<T> &v) {
  for (auto &x : v)
    is >> x;
  return is;
}
template <typename T> ostream &operator<<(ostream &os, vector<T> &v) {
  for (int i = 0; i < v.size(); i++) {
    cout << v[i];
    if (i != v.size() - 1)
      cout << endl;
  };
  return os;
}
template <typename T1, typename T2>
ostream &operator<<(ostream &os, pair<T1, T2> p) {
  cout << '(' << p.first << ',' << p.second << ')';
  return os;
}
template <typename T> void Out(T x) { cout << x << endl; }
template <typename T1, typename T2> void chOut(bool f, T1 y, T2 n) {
  if (f)
    Out(y);
  else
    Out(n);
}

using vec = vector<int>;
using mat = vector<vec>;
using Pii = pair<int, int>;
using v_bool = vector<bool>;
using v_Pii = vector<Pii>;

// int dx[4] = {1,0,-1,0};
// int dy[4] = {0,1,0,-1};
// char d[4] = {'D','R','U','L'};

const int mod = 1000000007;
// const int mod = 998244353;

struct Trie {

  static const int N_alphabet = 26;
  static const char begin_alphabet = 'a';
  using data_type = int;
  static const data_type not_exist = 0;

  Trie *next[N_alphabet];
  vector<data_type> val;

  Trie() {
    fill(next, next + N_alphabet, (Trie *)0);
    val = vec(26, 0);
  }

  // Sに対してval=vにupdate
  void insert(string &S, vec &num, int i = 0) {
    if (i < S.size()) {
      REP(j, 26) if (num[j] > 0) { val[j]++; }

      num[S[i] - begin_alphabet]--;
      if (this->next[S[i] - begin_alphabet] == NULL)
        this->next[S[i] - begin_alphabet] = new Trie();
      this->next[S[i] - begin_alphabet]->insert(S, num, i + 1);
    }
  }

  // Sのvalを求める、なければnot_existを返す
  data_type find(string &S, int i = 0) {
    if (i == S.size() - 1)
      return this->val[S[i] - 'a'];
    if (this->next[S[i] - begin_alphabet] == NULL)
      return not_exist;
    return this->next[S[i] - begin_alphabet]->find(S, i + 1);
  }
};

signed main() {

  int N;
  cin >> N;
  vector<string> S(N);
  cin >> S;

  v_Pii p(N);
  REP(i, N) p[i] = Pii(SZ(S[i]), i);
  Sort(p);
  Reverse(p);

  Trie T;

  long long ans = 0;
  REP(i, N) {
    int i0 = p[i].se;
    Reverse(S[i0]);
    ans += T.find(S[i0]);

    vec num(26);
    for (char c : S[i0])
      num[c - 'a']++;
    T.insert(S[i0], num);
  }
  Out(ans);

  return 0;
}


Error: 0

Fixed submission:

#include <bits/stdc++.h>
using namespace std;
struct fast_ios {
  fast_ios() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(20);
  };
} fast_ios_;
#define FOR(i, begin, end) for (int i = (begin); i < (end); i++)
#define REP(i, n) FOR(i, 0, n)
#define IFOR(i, begin, end) for (int i = (end)-1; i >= (begin); i--)
#define IREP(i, n) IFOR(i, 0, n)
#define Sort(v) sort(v.begin(), v.end())
#define Reverse(v) reverse(v.begin(), v.end())
#define all(v) v.begin(), v.end()
#define SZ(v) ((int)v.size())
#define Lower_bound(v, x)                                                      \\
  distance(v.begin(), lower_bound(v.begin(), v.end(), x))
#define Upper_bound(v, x)                                                      \\
  distance(v.begin(), upper_bound(v.begin(), v.end(), x))
#define chmax(a, b) a = max(a, b)
#define chmin(a, b) a = min(a, b)
#define bit(n) (1LL << (n))
#define debug(x) cout << #x << "=" << x << endl;
#define vdebug(v)                                                              \\
  {                                                                            \\
    cout << #v << "=" << endl;                                                 \\
    REP(i_debug, v.size()) { cout << v[i_debug] << ","; }                      \\
    cout << endl;                                                              \\
  }
#define mdebug(m)                                                              \\
  {                                                                            \\
    cout << #m << "=" << endl;                                                 \\
    REP(i_debug, m.size()) {                                                   \\
      REP(j_debug, m[i_debug].size()) { cout << m[i_debug][j_debug] << ","; }  \\
      cout << endl;                                                            \\
    }                                                                          \\
  }
#define pb push_back
#define fi first
#define se second
// #define int long long
// #define INF 1000000000000000000
template <typename T> istream &operator>>(istream &is, vector<T> &v) {
  for (auto &x : v)
    is >> x;
  return is;
}
template <typename T> ostream &operator<<(ostream &os, vector<T> &v) {
  for (int i = 0; i < v.size(); i++) {
    cout << v[i];
    if (i != v.size() - 1)
      cout << endl;
  };
  return os;
}
template <typename T1, typename T2>
ostream &operator<<(ostream &os, pair<T1, T2> p) {
  cout << '(' << p.first << ',' << p.second << ')';
  return os;
}
template <typename T> void Out(T x) { cout << x << endl; }
template <typename T1, typename T2> void chOut(bool f, T1 y, T2 n) {
  if (f)
    Out(y);
  else
    Out(n);
}

using vec = vector<int>;
using mat = vector<vec>;
using Pii = pair<int, int>;
using v_bool = vector<bool>;
using v_Pii = vector<Pii>;

// int dx[4] = {1,0,-1,0};
// int dy[4] = {0,1,0,-1};
// char d[4] = {'D','R','U','L'};

const int mod = 1000000007;
// const int mod = 998244353;

struct Trie {

  static const int N_alphabet = 26;
  static const char begin_alphabet = 'a';
  using data_type = int;
  static const data_type not_exist = 0;

  Trie *next[N_alphabet];
  data_type val = not_exist;

  Trie() { fill(next, next + N_alphabet, (Trie *)0); }

  // Sに対してval=vにupdate
  void insert(string &S, vec &num, int i = 0) {
    if (i < S.size()) {
      REP(j, 26) if (num[j] > 0) {
        if (this->next[j] == NULL)
          this->next[j] = new Trie();
        this->next[j]->val += 1;
      }

      num[S[i] - begin_alphabet]--;
      if (this->next[S[i] - begin_alphabet] == NULL)
        this->next[S[i] - begin_alphabet] = new Trie();
      this->next[S[i] - begin_alphabet]->insert(S, num, i + 1);
    }
  }

  // Sのvalを求める、なければnot_existを返す
  data_type find(string &S, int i = 0) {
    if (i == S.size())
      return this->val;
    if (this->next[S[i] - begin_alphabet] == NULL)
      return not_exist;
    return this->next[S[i] - begin_alphabet]->find(S, i + 1);
  }
};

signed main() {

  int N;
  cin >> N;
  vector<string> S(N);
  cin >> S;

  v_Pii p(N);
  REP(i, N) p[i] = Pii(SZ(S[i]), i);
  Sort(p);
  Reverse(p);

  Trie T;

  long long ans = 0;
  REP(i, N) {
    int i0 = p[i].se;
    Reverse(S[i0]);
    ans += T.find(S[i0]);

    vec num(26);
    for (char c : S[i0])
      num[c - 'a']++;
    T.insert(S[i0], num);
  }
  Out(ans);

  return 0;
}