Submission #3107157

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
using ll = long long;

// never fail to call build() !!
// constructor()
// add(string)
// match(string, f) : [left, right], f(int left, int right, int key) in right-asc left-desc order
/// --- AhoCorasick Library {{{ ///

struct AhoCorasick {
  struct Trie {
    unordered_map< char, Trie* > child;
    Trie* failure = nullptr;
    Trie* next = nullptr; // next failure that has the word
    int word = -1;
    Trie* add(char c) {
      if(child.count(c)) {
        return child[c];
      } else {
        return child[c] = new Trie;
      }
    }
    Trie* go(char c) {
      if(child.count(c)) {
        return child[c];
      } else {
        if(failure == nullptr) { // only top can come here
          return this;
        } else {
          return failure->go(c);
        }
      }
    }
  };
  Trie* top = new Trie;
  vector< string > dict;
  void add(string word) {
    Trie* now = top;
    for(size_t i = 0; i < word.size(); i++) {
      now = now->add(word[i]);
    }
    now->word = dict.size();
    dict.emplace_back(word);
  }
  void build() {
    queue< Trie* > q;
    q.emplace(top);
    while(q.size()) {
      Trie* now = q.front();
      q.pop();
      for(pair< char, Trie* > ch : now->child) {
        q.emplace(ch.second);
        Trie* failure = ch.second->failure = now == top ? top : now->failure->go(ch.first);
        ch.second->next = failure->word >= 0 ? failure : failure->next;
      }
    }
  }
  void match(string s, const function<void(int, int, int)> &f) {
    Trie* now = top;
    vector< tuple< int, int, int > > res;
    for(size_t i = 0; i < s.size(); i++) {
      now = now->go(s[i]);
      Trie* tmp = now;
      while(tmp != nullptr && tmp != top) {
        int word = tmp->word;
        if(word >= 0) {
          f(i - dict[word].size() + 1, i, word);
        }
        tmp = tmp->next;
      }
    }
  }
};

/// }}}--- ///

int main() {
  std::ios::sync_with_stdio(false), std::cin.tie(0);
  int n;
  cin >> n;
  AhoCorasick ecasd;
  for(int i = 0; i < n; i++) {
    string t;
    cin >> t;
    ecasd.add(t);
  }
  ecasd.build();
  string s;
  cin >> s;
  int m = s.size();
  const int mod = 1e9 + 7;
  vector< ll > dp(m + 1);
  dp[0] = 1;
  ecasd.match(s, [&](int le, int ri, int key) {
      dp[ri + 1] = (dp[ri + 1] + dp[le]) % mod;
      });
  cout << dp[m] << endl;
  return 0;
}

Submission Info

Judge Result