HDU 3065 病毒侵袭持续中 (AC自动机)
题意:找出模式串出现的种类是什么以及它们的次数
思路:拿一个数组存end的出现次数。
1 #include<iostream> 2 #include<cstdio> 3 #include<cstring> 4 #include<cmath> 5 #include<string> 6 #include<algorithm> 7 #include<queue> 8 #define maxn 50005 9 char s[2000005],a[1005][105]; 10 int n,num[1005]; 11 struct Trie{ 12 int fail[maxn],end[maxn],next[maxn][130],L,root; 13 int newnode(){ 14 for (int i=0;i<128;i++) 15 next[L][i]=-1; 16 end[L++]=-1; 17 return L-1; 18 } 19 void clear(){ 20 L=0; 21 root=newnode(); 22 } 23 void insert(char s[],int id){ 24 int now=root,len=strlen(s); 25 for (int i=0;i<len;i++){ 26 if (next[now][s[i]]==-1) next[now][s[i]]=newnode(); 27 now=next[now][s[i]]; 28 } 29 end[now]=id; 30 } 31 void build(){ 32 std::queue<int>Q; 33 int now=root; 34 for (int i=0;i<128;i++) 35 if (next[root][i]==-1) next[root][i]=root; 36 else{ 37 fail[next[root][i]]=root; 38 Q.push(next[root][i]); 39 } 40 while (!Q.empty()){ 41 now=Q.front();Q.pop(); 42 for (int i=0;i<128;i++){ 43 if (next[now][i]==-1) 44 next[now][i]=next[fail[now]][i]; 45 else{ 46 fail[next[now][i]]=next[fail[now]][i]; 47 Q.push(next[now][i]); 48 } 49 } 50 } 51 } 52 void query(char s[]){ 53 int len=strlen(s),now=root; 54 for (int i=0;i<=n;i++) 55 num[i]=0; 56 for (int i=0;i<len;i++){ 57 now=next[now][s[i]]; 58 int tmp=now; 59 while (tmp!=root){ 60 if (end[tmp]!=-1) 61 num[end[tmp]]++; 62 tmp=fail[tmp]; 63 } 64 } 65 for (int i=1;i<=n;i++) 66 if (num[i]){ 67 int len=strlen(a[i]); 68 for (int j=0;j<len;j++) 69 printf("%c",a[i][j]); 70 printf(": %d",num[i]); 71 printf("\n"); 72 } 73 } 74 }ac; 75 int main(){ 76 while (scanf("%d",&n)!=EOF){ 77 ac.clear(); 78 for (int i=1;i<=n;i++){ 79 scanf("%s",a[i]); 80 ac.insert(a[i],i); 81 } 82 ac.build(); 83 scanf("%s",s); 84 ac.query(s); 85 } 86 }
