【POJ】2278 DNA Sequence

各种wa后，各种TLE。注意若AC非法，则ACT等一定非法。而且尽量少MOD。

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

 #define MAXN 105
 #define NXTN 4

 char str[];

 typedef struct Matrix {
     int n;
     __int64 map[MAXN][MAXN];
     Matrix() {}
     Matrix(int nn) {
         n = nn;
         for (int i=; i<nn; ++i)
             for (int j=; j<nn; ++j)
                 map[i][j] = ;
     }
 } Matrix;

 int getval(char ch) {
     switch (ch) {
     case 'A': return ;
     case 'C': return ;
     case 'T': return ;
     case 'G': return ;
     default: return ;
     }
 }

 struct AC {
     int next[MAXN][NXTN], fail[MAXN], v[MAXN];
     int n, root;
     void init() {
         n = ;
         root = newNode();
     }
     int newNode() {
         fail[n] = ;
         v[n] = ;
         memset(next[n], -, sizeof(next[n]));
         return n++;
     }
     void create(char s[]) {
         int i = , id;
         int cur = root;

         while (s[i]) {
             id = getval(s[i]);
             ++i;
             if (next[cur][id] == -)
                 next[cur][id] = newNode();
             cur = next[cur][id];
         }
         v[cur] = ;
     }
     void build() {
         int i, cur;
         queue<int> Q;

         fail[root] = root;
         for (i=; i<NXTN; ++i) {
             if (next[root][i] == -)
                 next[root][i] = root;
             else {
                 fail[next[root][i]] = root;
                 Q.push(next[root][i]);
             }
         }

         while (!Q.empty()) {
             cur = Q.front();
             Q.pop();
             if (v[fail[cur]])    // important
                 v[cur] = ;
             for (i=; i<NXTN; ++i) {
                 if (next[cur][i] == -)
                     next[cur][i] = next[fail[cur]][i];
                 else {
                     fail[next[cur][i]] = next[fail[cur]][i];
                     Q.push(next[cur][i]);
                 }
             }
         }
     }
     Matrix query() {
         int i, j;

         Matrix mat(n);

         for (i=; i<n; ++i) {
             for (j=; j<NXTN; ++j) {
                 if (v[next[i][j]] == )
                     ++mat.map[i][next[i][j]];
             }
         }
         return mat;
     }
 };

 AC ac;

 Matrix mmul(Matrix a, Matrix b) {
     int i, j, k, n = a.n;
     Matrix ret(n);

     for (i=; i<n; ++i)
         for (j=; j<n; ++j)
             for (k=; k<n; ++k) {
                 ret.map[i][j] += a.map[i][k]*b.map[k][j];
                 ret.map[i][j] %= ;
             }
     return ret;
 }

 void mpow(Matrix a, int n) {
     Matrix ret(a.n);
     int i;
     __int64 ans;

     for (i=; i<ret.n; ++i)
         ret.map[i][i] = ;

     while (n) {
         if (n & )
             ret = mmul(ret, a);
         a = mmul(a, a);
         n >>= ;
     }

     ans = ;
     for (i=; i<ret.n; ++i) {
         //printf("i:%I64d\n", ret.map[0][i]);
         ans += ret.map[][i];
         ans %= ;
     }
     printf("%I64d\n", ans);
 }

 int main() {
     int m, n;
     int i;

     while (scanf("%d %d", &m, &n) != EOF) {
         ac.init();
         for (i=; i<m; ++i) {
             scanf("%s", str);
             ac.create(str);
         }
         ac.build();
         Matrix mat = ac.query();
         //printf("mat.n=%d\n", mat.n);
         mpow(mat, n);
     }

     return ;
 }