首先是参考胡浩大神的数组模拟指针的模板，超简洁。
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#include <cstdio> #include <cstdlib> #include <string> #include <climits> #include <iostream> #include <vector> #include <set> #include <cmath> #include <cctype> #include <algorithm> #include <sstream> #include <map> #include <cstring> #include <queue> using namespace std; //MAX_NODE = StringNumber * StringLength const int MAX_NODE = 101; //节点个数,一般字符形式的题26个 const int CHILD_NUM = 26; //特定题目需要 const int mod = 20090717; class ACAutomaton { private: //每个节点的儿子,即当前节点的状态转移 int chd[MAX_NODE][CHILD_NUM]; //记录题目给的关键数据 int val[MAX_NODE]; //传说中的fail指针 int fail[MAX_NODE]; //队列,用于广度优先计算fail指针 int Q[MAX_NODE]; //字母对应的ID int ID[128]; //已使用节点个数 int sz; //特定题目需要 int dp[2][MAX_NODE][1<<10]; public: //初始化,计算字母对应的儿子ID,如:'a'->0 ... 'z'->25 void Initialize() { fail[0] = 0; for (int i = 0 ; i < CHILD_NUM ; i ++) { ID[i+'a'] = i; } } //重新建树需先Reset void Reset() { memset(chd[0] , 0 , sizeof(chd[0])); sz = 1; } //将权值为key的字符串a插入到trie中 void Insert(char *a,int key) { int p = 0; for ( ; *a ; a ++) { int c = ID[*a]; if (!chd[p][c]) { memset(chd[sz] , 0 , sizeof(chd[sz])); val[sz] = 0; chd[p][c] = sz ++; } p = chd[p][c]; } val[p] = key; } //建立AC自动机,确定每个节点的权值以及状态转移 void Construct() { int *s = Q , *e = Q; for (int i = 0 ; i < CHILD_NUM ; i ++) { if (chd[0][i]) { fail[ chd[0][i] ] = 0; *e ++ = chd[0][i]; } } while (s != e) { int u = *s++; for (int i = 0 ; i < CHILD_NUM ; i ++) { int &v = chd[u][i]; if (v) { *e ++ = v; fail[v] = chd[ fail[u] ][i]; //以下一行代码要根据题目所给val的含义来写 val[v] |= val[ fail[v] ]; } else { v = chd[ fail[u] ][i]; } } } } //解题,特定题目需要 int Work(int n,int m,int k) { memset(dp[0] , 0 , sizeof(dp[0])); dp[0][0][0] = 1; int S = 0; while (n --) { int T = 1 - S; memset(dp[T] , 0 , sizeof(dp[T])); for (int i = 0 ; i < sz ; i ++) { for (int j = 0 ; j < m ; j ++) { if (dp[S][i][j]) { for (int k = 0 ; k < CHILD_NUM ; k ++) { int p = chd[i][k]; int st = (j | val[p]); dp[T][p][st] += dp[S][i][j]; if (dp[T][p][st] >= mod) { dp[T][p][st] -= mod; } } } } } S = T; } int ret = 0; for (int j = 0 ; j < m; j ++) { int cnt = 0; int a = j; for ( ; a ; cnt += (a&1) , a >>= 1); if (cnt < k) continue; for (int i = 0 ; i < sz ; i ++) { ret += dp[S][i][j]; if (ret >= mod) { ret -= mod; } } } return ret; } }AC; int main() { AC.Initialize(); int n , m , k; while (~scanf("%d%d%d",&n,&m,&k)) { if (n == 0 && m == 0 && k == 0) break; AC.Reset(); for (int i = 0 ; i < m ; i ++) { char temp[11]; scanf("%s",temp); AC.Insert(temp , 1 << i); } AC.Construct(); printf("%d\n",AC.Work(n , 1 << m , k)); } return 0; }
再其次是指针形式的：
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#define M 57 #define N 1000007 using namespace std; struct node { node *fail; node *next[26]; int cnt; void newnode()//生成节点 { fail = NULL; for (int i = 0; i < 26; ++i) { next[i] = NULL; } cnt = 0; } }; class Ac_Automat { node *q[N],H[N],*root; int fr,tl,t; public: // 初始化 void init() { fr = tl = 0; t = 0; H[t].newnode(); root = &H[t++]; } // 插入单词 void insert(char *s) { int i,k,len; len = strlen(s); node *p = root; for (i = 0; i < len; ++i) { k = s[i] - 'a'; if (p->next[k] == NULL) { H[t].newnode(); p->next[k] = &H[t++]; } p = p->next[k]; } p->cnt++; } // 建立失败指针 void build() { root->fail = NULL; q[tl] = root; while (fr <= tl) { node *tmp = q[fr++]; node *p = NULL; for (int i = 0; i < 26; ++i) { if (tmp->next[i]) { if (tmp == root) tmp->next[i]->fail = root; else { p = tmp->fail; while (p != NULL) { if (p->next[i]) { tmp->next[i]->fail = p->next[i]; break; } p = p->fail; } if (p == NULL) tmp->next[i]->fail = root; } q[++tl] = tmp->next[i]; } } } } // 查找 int query(char *s) { int res = 0; node *p = root; int len = strlen(s); for (int i = 0; i < len; ++i) { int k = s[i] - 'a'; while (p->next[k] == NULL && p != root) p = p->fail; p = p->next[k]; if (p == NULL) p = root; node *tmp = p; while (tmp != root && tmp->cnt != -1) { res += tmp->cnt; tmp->cnt = - 1; tmp = tmp->fail; } } return res; } }ac;
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