HDU 2594 Simpsons 'den den Talents

Classic extension 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 }