LA 3942 字典树 

 1 #include<iostream>
 2 #include<stdio.h>
 3 #include<string.h>
 4 #include<algorithm>
 5 #include<stdlib.h>
 6 #include<math.h>
 7 #include<queue>
 8 #include<vector>
 9 #include<map>
10 
11 const int maxnode=501000;
12 const int maxn=300100;
13 const int mod=20071027;
14 
15 using namespace std;
16 
17 int n,cas,d[maxn];
18 char s[maxn];
19 struct Trie
20 {
21     int ch[maxnode][26];
22     bool val[maxnode];
23     int sz;
24     Trie(){sz=1;memset(ch[0],0,sizeof(ch[0]));}
25     void reset(){sz=1;memset(ch[0],0,sizeof(ch[0]));}
26     int idx(char x){return x-'a';}
27     void insert(char *nw,int v)
28     {
29         int u=0,l=strlen(nw);
30         for(int i=0;i<l;i++)
31         {
32             int x=idx(nw[i]);
33             if (!ch[u][x]){
34                 memset(ch[sz],0,sizeof(ch[sz]));//边更新，边初始化
35                 val[sz]=0;
36                 ch[u][x]=sz++;
37             }
38             u=ch[u][x];
39         }
40         val[u]=v;
41     }
42     int search(int st)//查找s[i...len-1]的所有前缀
43     {
44         int u=0,l=strlen(s);
45         int ans=0;
46         for(int i=st;i<l;i++)
47         {
48             int x=idx(s[i]);
49             if (!ch[u][x]) return ans;
50             u=ch[u][x];
51             if(val[u])ans=(ans+d[i+1])%mod;//i+1是计算化简后的,记住标记
52         }
53         return ans;
54     }
55 }tree;//tree的定义要放到main的外面
56 
57 int main()
58 {
59     cas=0;
60     while(scanf("%s",s)==1)
61     {
62         scanf("%d",&n);
63         cas++;
64         tree.reset();
65         char word[maxn];
66         for(int i=0;i<n;i++)
67         {
68             cin>>word;tree.insert(word,1);
69         }
70         int len=strlen(s);
71         memset(d,0,sizeof(d));
72         d[len]=1;
73         for(int i=len-1;i>=0;i--)
74         d[i]=tree.search(i);
75         printf("Case %d: %d\n",cas,d[0]);
76 //        cout<<"Case "<<cas<<": "<<d[0]<<endl;
77     }
78     return 0;
79 }

 

posted @ 2014-02-26 21:08  little_w  阅读(219)  评论(0)    收藏  举报