BZOJ 4327:[JSOI2012]玄武密码

对于询问串建AC自动机，用母串匹配，标记访问过的节点不再被访问，最后枚举每个串统计答案

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#include<cstdio> #include<cstring> using namespace std; int cnt,tree[10000005][5],a[10000005],len[100005],Fail[10000005],vis[10000005],q[10000005]; char s[10000005],S[100005][105]; void update(int x){     for (int i=0; i<4; i++)         if (!tree[x][i]) tree[x][i]=tree[Fail[x]][i]; } void ac_(){     int head=0,tail=0;     vis[0]=1;     for (int i=0; i<4; i++)         if (tree[0][i]){             update(tree[0][i]);             q[++tail]=tree[0][i];             vis[tree[0][i]]=1;         }     while (head<tail){         int x=q[++head];         for (int i=0; i<4; i++){             int V=tree[x][i];             if (vis[V]) continue;             Fail[V]=tree[Fail[x]][i];             update(V);             vis[V]=1;             q[++tail]=V;         }     } } int main(){     int n,m;     scanf("%d%d",&n,&m);     scanf("%s",s+1);     for (int i=1; i<=n; i++){         if (s[i]=='E') a[i]=0;         else if (s[i]=='S') a[i]=1;         else if (s[i]=='W') a[i]=2;         else a[i]=3;     }     for (int i=1; i<=m; i++){         scanf("%s",S[i]+1);         len[i]=strlen(S[i]+1);         int now=0;         for (int j=1; j<=len[i]; j++){             int x;             if (S[i][j]=='E') x=0;             else if (S[i][j]=='S') x=1;             else if (S[i][j]=='W') x=2;             else x=3;             if (!tree[now][x]) tree[now][x]=++cnt;             now=tree[now][x];         } //      sz[now]=1;     }     ac_(); //  printf("%d\n",tree[1][3]);     memset(vis,0,sizeof(vis));     int now=0;     for (int i=1; i<=n; i++){         now=tree[now][a[i]]; //      printf("%d ",now);         if (!vis[now]){             int Pre=now;             vis[Pre]=1;             Pre=Fail[Pre];             while (!vis[Pre]){                 vis[Pre]=1;                 Pre=Fail[Pre];             }         }     } //  printf("\n");     for (int i=1; i<=m; i++){         int now=0,maxlen=0;         for (int j=1; j<=len[i]; j++){             int x;             if (S[i][j]=='E') x=0;             else if (S[i][j]=='S') x=1;             else if (S[i][j]=='W') x=2;             else x=3;             now=tree[now][x];             if (!vis[now]) break;             maxlen=j;         }         printf("%d\n",maxlen);     }     return 0; }