【POJ】2278 DNA Sequence

  1 #include <iostream>
  2 #include <cstdio>
  3 #include <cstring>
  4 #include <queue>
  5 using namespace std;
  6 
  7 #define MAXN 105
  8 #define NXTN 4
  9 
 10 char str[15];
 11 
 12 typedef struct Matrix {
 13     int n;
 14     __int64 map[MAXN][MAXN];
 15     Matrix() {}
 16     Matrix(int nn) {
 17         n = nn;
 18         for (int i=0; i<nn; ++i)
 19             for (int j=0; j<nn; ++j)
 20                 map[i][j] = 0;
 21     }
 22 } Matrix;
 23 
 24 int getval(char ch) {
 25     switch (ch) {
 26     case ‘A‘: return 0;
 27     case ‘C‘: return 1;
 28     case ‘T‘: return 2;
 29     case ‘G‘: return 3;
 30     default: return 0;
 31     }
 32 }
 33 
 34 struct AC {
 35     int next[MAXN][NXTN], fail[MAXN], v[MAXN];
 36     int n, root;
 37     void init() {
 38         n = 0;
 39         root = newNode();
 40     }
 41     int newNode() {
 42         fail[n] = 0;
 43         v[n] = 0;
 44         memset(next[n], -1, sizeof(next[n]));
 45         return n++;
 46     }
 47     void create(char s[]) {
 48         int i = 0, id;
 49         int cur = root;
 50 
 51         while (s[i]) {
 52             id = getval(s[i]);
 53             ++i;
 54             if (next[cur][id] == -1)
 55                 next[cur][id] = newNode();
 56             cur = next[cur][id];
 57         }
 58         v[cur] = 1;
 59     }
 60     void build() {
 61         int i, cur;
 62         queue<int> Q;
 63 
 64         fail[root] = root;
 65         for (i=0; i<NXTN; ++i) {
 66             if (next[root][i] == -1)
 67                 next[root][i] = root;
 68             else {
 69                 fail[next[root][i]] = root;
 70                 Q.push(next[root][i]);
 71             }
 72         }
 73 
 74         while (!Q.empty()) {
 75             cur = Q.front();
 76             Q.pop();
 77             if (v[fail[cur]])    // important
 78                 v[cur] = 1;
 79             for (i=0; i<NXTN; ++i) {
 80                 if (next[cur][i] == -1)
 81                     next[cur][i] = next[fail[cur]][i];
 82                 else {
 83                     fail[next[cur][i]] = next[fail[cur]][i];
 84                     Q.push(next[cur][i]);
 85                 }
 86             }
 87         }
 88     }
 89     Matrix query() {
 90         int i, j;
 91 
 92         Matrix mat(n);
 93 
 94         for (i=0; i<n; ++i) {
 95             for (j=0; j<NXTN; ++j) {
 96                 if (v[next[i][j]] == 0)
 97                     ++mat.map[i][next[i][j]];
 98             }
 99         }
100         return mat;
101     }
102 };
103 
104 AC ac;
105 
106 Matrix mmul(Matrix a, Matrix b) {
107     int i, j, k, n = a.n;
108     Matrix ret(n);
109 
110     for (i=0; i<n; ++i)
111         for (j=0; j<n; ++j)
112             for (k=0; k<n; ++k) {
113                 ret.map[i][j] += a.map[i][k]*b.map[k][j];
114                 ret.map[i][j] %= 100000;
115             }
116     return ret;
117 }
118 
119 void mpow(Matrix a, int n) {
120     Matrix ret(a.n);
121     int i;
122     __int64 ans;
123 
124     for (i=0; i<ret.n; ++i)
125         ret.map[i][i] = 1;
126 
127     while (n) {
128         if (n & 1)
129             ret = mmul(ret, a);
130         a = mmul(a, a);
131         n >>= 1;
132     }
133 
134     ans = 0;
135     for (i=0; i<ret.n; ++i) {
136         //printf("i:%I64d\n", ret.map[0][i]);
137         ans += ret.map[0][i];
138         ans %= 100000;
139     }
140     printf("%I64d\n", ans);
141 }
142 
143 int main() {
144     int m, n;
145     int i;
146 
147     while (scanf("%d %d", &m, &n) != EOF) {
148         ac.init();
149         for (i=0; i<m; ++i) {
150             scanf("%s", str);
151             ac.create(str);
152         }
153         ac.build();
154         Matrix mat = ac.query();
155         //printf("mat.n=%d\n", mat.n);
156         mpow(mat, n);
157     }
158 
159     return 0;
160 }