KMP算法模板

不懂的话推荐看这篇博客，讲的很清楚 http://blog.csdn.net/v_july_v/article/details/7041827

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<cstring>
 4 using namespace std;
 5 const int maxlen=1024;
 6 char S[maxlen],T[maxlen],next[maxlen];
 7 void get_next()
 8 {
 9     next[0]=-1;
10     int i=0,j=-1;
11     while(i<strlen(T)-1){
12         if(j==-1||T[i]==T[j]){
13             i++;j++;
14             if(T[i]!=T[j])
15                 next[i]=j;
16             else next[i]=next[j];
17         }else j=next[j];
18     }
19 }
20 int KMP()
21 {
22     int slen=strlen(S),tlen=strlen(T);
23     get_next();
24     int i=0,j=0;
25     while(i<slen&&j<tlen){
26         if(j==-1||S[i]==T[j]){
27             i++;j++;
28         }else{
29             j=next[j];
30         }
31     }
32     if(j==tlen) return i-j;
33     else return -1;
34 }
35 int main()
36 {
37     scanf("%s",S);
38     scanf("%s",T);
39     cout<<KMP()+1;
40     return 0;
41 }