HDU 2594 Simpsons’ Hidden Talents

经典扩展kmp。

 

 1 #include <iostream>
 2 #include <cstring>
 3 #include <cstdio>
 4 using namespace std;
 5 
 6 void getA (char *T,int *A){
 7     int j=0;
 8     int len=strlen (T);
 9     while(1+j<len&&T[0+j]==T[1+j])
10         j = j + 1;
11     A[1]=j;
12     int k=1;
13     for(int i=2; i<len; i++){
14         int Len = k + A[k] - 1,L = A[i-k];
15         if( L < Len - i + 1 )
16             A[i] = L;
17             else{
18                 j = max(0,Len -i +1);
19                 while(i+j<len&&T[i+j] == T[0+j])
20                     j = j + 1;
21                 A[i] = j,k = i;
22             }
23     }
24 }
25 
26 void getB (char *S,char *T,int *A,int *B){
27     getA (T,A);
28     int j = 0;
29     int lens=strlen (S);
30     int lent=strlen (T);
31     while(j<lens&&j<lent&&T[0+j]==S[0+j])
32             j = j + 1;
33     B[0] = j;
34     int k = 0;
35     for(int i=1; i<lens; i++) {
36         int Len = k + B[k] - 1,L = A[i-k];
37         if( L < Len - i + 1 )
38             B[i] = L;
39         else {
40             j = max(0,Len -i +1);
41             while(i+j<lens&&j<lent&&S[i+j] == T[0+j])
42                 j = j + 1;
43                 B[i] = j,k = i;
44         }
45     }
46 }
47 
48     char S[200000],T[200000];
49     int A[200000],B[200000];
50 int main (){
51     while (~scanf ("%s %s",S,T)){
52         getB (T,S,A,B);
53         int lent=strlen(T);
54         int ans=0;
55         for (int i=0;i<lent;i++){
56             if (i+B[i]==lent){
57                 ans=B[i];
58                 break ;
59             }
60             //cout<<B[i]<<" ";
61         }
62         if (ans){
63             for (int i=0;i<ans;i++)
64                 printf ("%c",S[i]);
65             printf (" ");
66         }
67         cout<<ans<<endl;
68     }
69     return 0;
70 }