string/aho-corasick.hpp

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• Last update: 2020-12-10 19:54:55+09:00
• Include: #include "string/aho-corasick.hpp"

Depends on

• string/trie.hpp

Verified with

• verify/verify-yuki/yuki-1269.test.cpp

Code

#pragma once

#include "trie.hpp"

template <size_t X = 26, char margin = 'a'>
struct AhoCorasick : Trie<X + 1, margin> {
  using TRIE = Trie<X + 1, margin>;
  using TRIE::next;
  using TRIE::st;
  using TRIE::TRIE;
  vector<int> cnt;

  void build(int heavy = true) {
    int n = st.size();
    cnt.resize(n);
    for (int i = 0; i < n; i++) {
      if (heavy) sort(st[i].idxs.begin(), st[i].idxs.end());
      cnt[i] = st[i].idxs.size();
    }

    queue<int> que;
    for (int i = 0; i < (int)X; i++) {
      if (~next(0, i)) {
        next(next(0, i), X) = 0;
        que.emplace(next(0, i));
      } else {
        next(0, i) = 0;
      }
    }

    while (!que.empty()) {
      auto &x = st[que.front()];
      int fail = x.nxt[X];

      cnt[que.front()] += cnt[fail];
      que.pop();

      for (int i = 0; i < (int)X; i++) {
        int &nx = x.nxt[i];
        if (nx < 0) {
          nx = next(fail, i);
          continue;
        }
        que.emplace(nx);
        next(nx, X) = next(fail, i);
        if (heavy) {
          auto &idx = st[nx].idxs;
          auto &idy = st[next(fail, i)].idxs;
          vector<int> idz;
          set_union(idx.begin(), idx.end(), idy.begin(), idy.end(),
                    back_inserter(idz));
          idx = idz;
        }
      }
    }
  }

  vector<int> match(string s, int heavy = true) {
    vector<int> res(heavy ? TRIE::size() : 1);
    int pos = 0;
    for (auto &c : s) {
      pos = next(pos, c - margin);
      if (heavy)
        for (auto &x : st[pos].idxs) res[x]++;
      else
        res[0] += cnt[pos];
    }
    return res;
  }

  int count(int pos) { return cnt[pos]; }
};

#line 2 "string/aho-corasick.hpp"

#line 2 "string/trie.hpp"

template <size_t X = 26, char margin = 'a'>
struct Trie {
  struct Node {
    array<int, X> nxt;
    vector<int> idxs;
    int idx;
    char key;
    Node(char c) : idx(-1), key(c) { fill(nxt.begin(), nxt.end(), -1); }
  };

  vector<Node> st;

  Trie(char c = '$') { st.emplace_back(c); }

  inline int &next(int i, int j) { return st[i].nxt[j]; }

  void add(const string &s, int x) {
    int pos = 0;
    for (int i = 0; i < (int)s.size(); i++) {
      int k = s[i] - margin;
      if (~next(pos, k)) {
        pos = next(pos, k);
        continue;
      }
      int npos = st.size();
      next(pos, k) = npos;
      st.emplace_back(s[i]);
      pos = npos;
    }
    st[pos].idx = x;
    st[pos].idxs.emplace_back(x);
  }

  int find(const string &s) {
    int pos = 0;
    for (int i = 0; i < (int)s.size(); i++) {
      int k = s[i] - margin;
      if (next(pos, k) < 0) return -1;
      pos = next(pos, k);
    }
    return pos;
  }

  int move(int pos, char c) {
    assert(pos < (int)st.size());
    return pos < 0 ? -1 : next(pos, c - margin);
  }

  int size() const { return st.size(); }

  int idx(int pos) { return pos < 0 ? -1 : st[pos].idx; }

  vector<int> idxs(int pos) { return pos < 0 ? vector<int>() : st[pos].idxs; }
};
#line 4 "string/aho-corasick.hpp"

template <size_t X = 26, char margin = 'a'>
struct AhoCorasick : Trie<X + 1, margin> {
  using TRIE = Trie<X + 1, margin>;
  using TRIE::next;
  using TRIE::st;
  using TRIE::TRIE;
  vector<int> cnt;

  void build(int heavy = true) {
    int n = st.size();
    cnt.resize(n);
    for (int i = 0; i < n; i++) {
      if (heavy) sort(st[i].idxs.begin(), st[i].idxs.end());
      cnt[i] = st[i].idxs.size();
    }

    queue<int> que;
    for (int i = 0; i < (int)X; i++) {
      if (~next(0, i)) {
        next(next(0, i), X) = 0;
        que.emplace(next(0, i));
      } else {
        next(0, i) = 0;
      }
    }

    while (!que.empty()) {
      auto &x = st[que.front()];
      int fail = x.nxt[X];

      cnt[que.front()] += cnt[fail];
      que.pop();

      for (int i = 0; i < (int)X; i++) {
        int &nx = x.nxt[i];
        if (nx < 0) {
          nx = next(fail, i);
          continue;
        }
        que.emplace(nx);
        next(nx, X) = next(fail, i);
        if (heavy) {
          auto &idx = st[nx].idxs;
          auto &idy = st[next(fail, i)].idxs;
          vector<int> idz;
          set_union(idx.begin(), idx.end(), idy.begin(), idy.end(),
                    back_inserter(idz));
          idx = idz;
        }
      }
    }
  }

  vector<int> match(string s, int heavy = true) {
    vector<int> res(heavy ? TRIE::size() : 1);
    int pos = 0;
    for (auto &c : s) {
      pos = next(pos, c - margin);
      if (heavy)
        for (auto &x : st[pos].idxs) res[x]++;
      else
        res[0] += cnt[pos];
    }
    return res;
  }

  int count(int pos) { return cnt[pos]; }
};

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