记录个DFA的模版POJ2778

DFA+矩阵乘法

#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;

typedef long long llg;

const int N = 105;
const int P = 100000;

struct node
{
    int flag, index;
    node *pre, *next[4];
    void init()
    {
        flag = index = 0;
        pre = 0;
        memset(next, 0, sizeof(next));
    }
}trie[N];

node *root, *queue[N];
int m, tot, n;
llg matrix[N][N], c[N][N];
char str[15];

int getCode(char c)
{
    switch(c)
    {
        case 'A': return  0;
        case 'T': return  1;
        case 'G': return  2;
        case 'C': return  3;
        default: cout<<"input error a??"<<endl;
    }
}

void insertString(node *root, char *str)
{
    int i, lab, len = strlen(str);
    for(i = 0; i < len; i++)
    {
        lab = getCode(str[i]);
        if(root->next[lab] == 0)
        {
            root->next[lab] = &trie[++tot];
            root->next[lab]->init();
            root->next[lab]->index = tot;
        }
        root = root->next[lab];
    }
    root->flag = 1;
}

void buildAC()
{
    int i, head, tail;
    node *u, *tmp;
    root->pre = root;
    head = tail = 0;
    queue[0] = root;
    while(head <= tail)
    {
        u = queue[head++];
        for(i = 0; i < 4; i++)
            if(u->next[i] == 0)
            {
                if(u == root)  u->next[i] = root;
                else  u->next[i] = u->pre->next[i];
            }
            else
            {
                if(u == root)  u->next[i]->pre = root;
                else  u->next[i]->pre = u->pre->next[i];
                queue[++tail] = u->next[i];
            }
        tmp = u->pre;
        if(u->flag == 0)
        while(tmp != root)
        {
            if(tmp->flag)
            {
                u->flag = 1;
                break;
            }
            tmp = tmp->pre;
        }
    }
}

void generateMatrix()
{
    int i, j;
    node *u;
    memset(matrix, 0, sizeof(matrix));
    for(i = 0; i <= tot; i++)
    {
        u = &trie[i];
        if(u->flag == 0)
            for(j = 0; j < 4; j++)
                if(u->next[j]->flag == 0)
                    matrix[i][u->next[j]->index]++;
    }
}

void multiply(llg a[][N], llg b[][N], llg target[][N])
{
    int i, j, k;
    llg tmp[N][N];
    for(i = 0; i <= tot; i++)
        for(j = 0; j <= tot; j++)
        {
            tmp[i][j] = 0;
            for(k = 0; k <= tot; k++)
                tmp[i][j] += a[i][k]*b[k][j];
            tmp[i][j] %= P;
        }
    for(i = 0; i <= tot; i++)
        for(j = 0; j <= tot; j++)
            target[i][j] = tmp[i][j];
}

void calAns(int n)
{
    int i, j;
    llg ans = 0;
    for(i = 0; i <= tot; i++)
        for(j = 0; j <= tot; j++)
            c[i][j] = matrix[i][j];
    n--;
    while(n)
    {
        if(n & 1)  multiply(c, matrix, c);
        multiply(matrix, matrix, matrix);
        n >>= 1;
    }
    for(i = 0; i <= tot; i++)  ans = (ans + c[0][i]) % P;
    printf("%I64d\n", ans);
}

int main()
{
    int i;
    scanf("%d%d", &m, &n);
    tot = 0;
    root = &trie[0];
    root->init();
    for(i = 0; i < m; i++)
    {
        scanf(" %s", str);
        insertString(root, str);
    }
    buildAC();
    generateMatrix();
    calAns(n);
    return 0;
}