Algorithms-Notebook/Aho Corsik.cpp at master · phpduke/Algorithms-Notebook · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
#define inc(i,a,b)      for(int i=a;i<=b;++i)
#define pb              push_back

const int maxWords = 506, maxLyrics = 106, maxWordLength = 5006, maxLyricLength = 50006;

struct node {
    int occ, failIndegree;
    map<char,node*> edge;
    node* fail;

    node():occ(0),failIndegree(0),fail(NULL) {}
}root;

int numWords, numLyrics;
node* id[maxWords];

void preComputation();
void searchTarget();
void getOccurances();
void buildTrie();
void buildAutomaton();

int main() {
    scanf("%d",&numWords);
    preComputation();

    scanf("%d",&numLyrics);
    inc(i,1,numLyrics) {
        searchTarget();
    }
    getOccurances();

    inc(i,0,numWords-1) {
        printf("%d\n",id[i]->occ);
    }
}

void buildTrie() {
    char word[maxWordLength], c;

    inc(i,0,numWords-1) {
        cin >> word;
        id[i] = &root;

        for(int j=0;word[j];++j) {
            c = word[j];
            assert(isalnum(c) || c=='-');
            if(!id[i]->edge.count(c)) {
                id[i]->edge[c] = new node;
            }
            id[i] = id[i]->edge[c];
        }
    }
}
void buildAutomaton() {
    queue<node*> q;

    vector<char> alpha;
    inc(i,'a','z') alpha.pb(i);
    inc(i,'A','Z') alpha.pb(i);
    inc(i,'0','9') alpha.pb(i);
    alpha.pb('-');

    // Gives root more failIndegree so that it isn't added to queue in getOccurances()
    root.failIndegree = 1;

    inc(i,0,alpha.size()-1) {
        if(!root.edge.count(alpha[i])) {
            root.edge[alpha[i]] = &root;
        }
        else {
            root.edge[alpha[i]]->fail = &root;
            (root.failIndegree)++;
            q.push(root.edge[alpha[i]]);
        }
    }

    while(!q.empty()) {
        node* p = q.front();
        q.pop();

        map<char,node*>::iterator it = p->edge.begin();
        for(;it!=p->edge.end();++it) {
            node *u = it->second;
            char c = it->first;

            node *v = p->fail;
            while(!v->edge.count(c)) {

                v = v->fail;
            }
            u->fail = v->edge[c];
            (v->edge[c]->failIndegree)++;

            q.push(u);
        }
    }
}
void preComputation() {
    buildTrie();
    buildAutomaton();
}
void searchTarget() {
    char lyric[maxLyricLength];
    scanf(" %s",lyric);

    node* curr = &root;
    char c;
    for(int i=0;lyric[i];++i) {
        c = lyric[i];
        while(!curr->edge.count(c)) {
            assert(curr->fail != NULL);
            curr = curr->fail;
        }
        curr = curr->edge[c];
        (curr->occ)++;
    }
}
void getOccurances() {
    queue<node*> q;

    queue<node*> bfs;
    bfs.push(&root);
    while(!bfs.empty()) {
        node* u = bfs.front();
        bfs.pop();

        if(!u->failIndegree) q.push(u);

        map<char,node*>::iterator it = u->edge.begin();
        for(;it!=u->edge.end();++it) {
            node* v = it->second;
            if(v!=(&root)) bfs.push(v);
        }
    }

    while(!q.empty()) {
        node* u = q.front();
        q.pop();

        assert(u->fail != NULL);
        node* v = u->fail;

        (v->failIndegree)--;
        if(!v->failIndegree) {
            assert(v!=(&root));
            q.push(v);
        }

        v->occ += u->occ;
    }
}