Cod sursa(job #1177661)

Utilizator a_h1926Heidelbacher Andrei a_h1926 Data 26 aprilie 2014 13:10:27
Problema Aho-Corasick Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 3.27 kb
#include <fstream>
#include <vector>
#include <algorithm>
#include <string>

using namespace std;

class AhoCorasickAutomaton {
  public:
    static const int NIL = -1;
    static const int SIGMA = 26;

    AhoCorasickAutomaton(const vector<string> &signatures):
      size(1),
      start(0),
      delta(vector< vector<int> >(1, vector<int>(SIGMA, NIL))),
      pi(vector<int>(1, 0)),
      order(vector<int>()),
      signatureCount(int(signatures.size())),
      signatureIndices(vector< vector<int> >(1, vector<int>())) {
        for (int i = 0; i < signatureCount; ++i) {
            int x = start;
            for (int j = 0; j < int(signatures[i].length()); x = delta[x][Encode(signatures[i][j++])])
                if (delta[x][Encode(signatures[i][j])] == NIL)
                    delta[x][Encode(signatures[i][j])] = NewNode();
            signatureIndices[x].push_back(i);
        }
        order.push_back(start);
        for (int i = 0; i < int(order.size()); ++i) {
            int x = order[i];
            for (int symbol = 0; symbol < SIGMA; ++symbol) {
                int p = pi[x];
                for (; p != start && delta[p][symbol] == NIL; p = pi[p]);
                if (delta[p][symbol] != NIL && delta[p][symbol] != delta[x][symbol])
                    p = delta[p][symbol];
                if (delta[x][symbol] == NIL) {
                    delta[x][symbol] = p;
                } else {
                    pi[delta[x][symbol]] = p;
                    order.push_back(delta[x][symbol]);
                }
            }
        }
        reverse(order.begin(), order.end());
    }

    vector<int> GetMatches(const string &stringToSearch) {
        vector<int> nodeMatches = vector<int>(size, 0);
        for (int x = start, i = 0; i < int(stringToSearch.length()); ++i)
            ++nodeMatches[x = delta[x][Encode(stringToSearch[i])]];
        for (int i = 0; order[i] != start; ++i)
            nodeMatches[pi[order[i]]] += nodeMatches[order[i]];
        vector<int> signatureMatches = vector<int>(signatureCount, 0);
        for (int x = 0; x < size; ++x)
            for (int i = 0; i < int(signatureIndices[x].size()); ++i)
                signatureMatches[signatureIndices[x][i]] += nodeMatches[x];
        return signatureMatches;
    }

  private:
    int size, start;
    vector< vector<int> > delta;
    vector<int> pi, order;
    int signatureCount;
    vector< vector<int> > signatureIndices;

    static int Encode(const char symbol) {
        return int(symbol - 'a');
    }

    int NewNode() {
        delta.push_back(vector<int>(SIGMA, NIL));
        pi.push_back(start);
        signatureIndices.push_back(vector<int>());
        return size++;
    }
};

int main() {
    ifstream in("ahocorasick.in");
    ofstream out("ahocorasick.out");
    string stringToSearch;
    in >> stringToSearch;
    int n;
    in >> n;
    vector<string> signatures = vector<string>(n, "");
    for (int i = 0; i < n; ++i)
        in >> signatures[i];
    AhoCorasickAutomaton automaton = AhoCorasickAutomaton(signatures);
    vector<int> matches = automaton.GetMatches(stringToSearch);
    for (int i = 0; i < int(matches.size()); ++i)
        out << matches[i] << "\n";
    in.close();
    out.close();
    return 0;
}