HDU 2594 Simpsons’ Hidden Talents

经典扩展kmp。

#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;

void getA (char *T,int *A){
    int j=0;
    int len=strlen (T);
    while(1+j<len&&T[0+j]==T[1+j])
        j = j + 1;
    A[1]=j;
    int k=1;
    for(int i=2; i<len; i++){
        int Len = k + A[k] - 1,L = A[i-k];
        if( L < Len - i + 1 )
            A[i] = L;
            else{
                j = max(0,Len -i +1);
                while(i+j<len&&T[i+j] == T[0+j])
                    j = j + 1;
                A[i] = j,k = i;
            }
    }
}

void getB (char *S,char *T,int *A,int *B){
    getA (T,A);
    int j = 0;
    int lens=strlen (S);
    int lent=strlen (T);
    while(j<lens&&j<lent&&T[0+j]==S[0+j])
            j = j + 1;
    B[0] = j;
    int k = 0;
    for(int i=1; i<lens; i++) {
        int Len = k + B[k] - 1,L = A[i-k];
        if( L < Len - i + 1 )
            B[i] = L;
        else {
            j = max(0,Len -i +1);
            while(i+j<lens&&j<lent&&S[i+j] == T[0+j])
                j = j + 1;
                B[i] = j,k = i;
        }
    }
}

    char S[200000],T[200000];
    int A[200000],B[200000];
int main (){
    while (~scanf ("%s %s",S,T)){
        getB (T,S,A,B);
        int lent=strlen(T);
        int ans=0;
        for (int i=0;i<lent;i++){
            if (i+B[i]==lent){
                ans=B[i];
                break ;
            }
            //cout<<B[i]<<" ";
        }
        if (ans){
            for (int i=0;i<ans;i++)
                printf ("%c",S[i]);
            printf (" ");
        }
        cout<<ans<<endl;
    }
    return 0;
}