【POJ】2778 DNA Sequence

  1 #include<cstdio>

  2 #include<cstring>

  3 #include<queue>

  4 typedef long long LL;

  5 #define MAXN 110

  6 #define MOD 100000

  7 using namespace std;

  8 char str[MAXN];

  9 int size;

 10 struct Matrix {

 11     LL mat[MAXN][MAXN];

 12     void Zero() {

 13         memset(mat, 0, sizeof(mat));

 14     }

 15     void Unit() {

 16         int i;

 17         for (i = 0; i <= size; i++)

 18             mat[i][i] = 1;

 19     }

 20 };

 21 struct Trie {

 22     int fail, next[4];

 23     bool end;

 24     void Init() {

 25         fail = 0;

 26         end = false;

 27         memset(next, 0, sizeof(next));

 28     }

 29 };

 30 Matrix a, b;

 31 Trie tree[MAXN];

 32 Matrix operator *(const Matrix &a, const Matrix &b) {

 33     Matrix temp;

 34     int i, j, k;

 35     temp.Zero();

 36     for (i = 0; i <= size; i++) {

 37         for (j = 0; j <= size; j++) {

 38             for (k = 0; k <= size; k++)

 39                 temp.mat[i][j] += a.mat[i][k] * b.mat[k][j];

 40             temp.mat[i][j] %= MOD;

 41         }

 42     }

 43     return temp;

 44 }

 45 inline int GET(char ch) {

 46     if (ch == 'A')

 47         return 0;

 48     if (ch == 'C')

 49         return 1;

 50     if (ch == 'G')

 51         return 2;

 52     return 3;

 53 }

 54 void Insert(char *s) {

 55     int now, t;

 56     for (now = 0; *s; s++) {

 57         t = GET(*s);

 58         if (!tree[now].next[t]) {

 59             tree[++size].Init();

 60             tree[now].next[t] = size;

 61         }

 62         now = tree[now].next[t];

 63     }

 64     tree[now].end = true;

 65 }

 66 void BFS() {

 67     int now, i, p;

 68     queue<int> q;

 69     q.push(0);

 70     while (!q.empty()) {

 71         now = q.front();

 72         q.pop();

 73         for (i = 0; i < 4; i++) {

 74             if (tree[now].next[i]) {

 75                 p = tree[now].next[i];

 76                 if (now)

 77                     tree[p].fail = tree[tree[now].fail].next[i];

 78                 tree[p].end |= tree[tree[p].fail].end;

 79                 q.push(p);

 80             } else

 81                 tree[now].next[i] = tree[tree[now].fail].next[i];

 82         }

 83     }

 84 }

 85 void DoIt(int m) {

 86     int i, j, p;

 87     a.Zero();

 88     for (i = 0; i <= size; i++) {

 89         for (j = 0; j < 4; j++) {

 90             if (!tree[i].end) {

 91                 p = tree[i].next[j];

 92                 if (p) {

 93                     if (!tree[p].end)

 94                         a.mat[i][p]++;

 95                 } else

 96                     a.mat[i][0]++;

 97             }

 98         }

 99     }

100     b.Zero();

101     b.Unit();

102     for (; m; m >>= 1) {

103         if (m & 1)

104             b = b * a;

105         a = a * a;

106     }

107 }

108 int main() {

109     LL ans;

110     int n, m, i;

111     while (~scanf("%d%d", &n, &m)) {

112         tree[0].Init();

113         for (size = i = 0; i < n; i++) {

114             scanf(" %s", str);

115             Insert(str);

116         }

117         BFS();

118         DoIt(m);

119         for (ans = i = 0; i <= size; i++)

120             ans += b.mat[0][i];

121         printf("%lld\n", ans % MOD);

122     }

123     return 0;

124 }