hdu 3613 Best Reward 扩展kmp

#include<iostream>
#include<cstring>
#include<cstdio>
using namespace std;
const int MM=500100;
int next1[MM],extand1[MM];
int next2[MM],extand2[MM];
int sum[MM];
char S[MM],T[MM];
int val[30];
void GetNext(const char *T,int *next){
int len=strlen(T),a=0;
next[0]=len;
while(a<len-1 && T[a]==T[a+1]) a++;
next[1]=a;
a=1;
for(int k=2;k<len;k++){
int p=a+next[a]-1,L=next[k-a];
if( (k-1)+L >= p){
int j = (p-k+1)>0 ? (p-k+1) : 0;
while(k+j<len && T[k+j]==T[j]) j++;
next[k]=j;
a=k;
}
else
next[k]=L;
}
}
void GetExtand(const char *S,const char *T,int *next,int *extand){
GetNext(T,next);
int slen=strlen(S),tlen=strlen(T),a=0;
int MinLen = slen < tlen ? slen : tlen;
while(a<MinLen && S[a]==T[a]) a++;
extand[0]=a;
a=0;
for(int k=1;k<slen;k++){
int p=a+extand[a]-1, L=next[k-a];
if( (k-1)+L >= p){
int j= (p-k+1) > 0 ? (p-k+1) : 0;
while(k+j<slen && j<tlen && S[k+j]==T[j]) j++;
extand[k]=j;
a=k;
}
else
extand[k]=L;
}
}

int main()
{
int cas;
scanf("%d",&cas);
while(cas--)
{
int now=-1;
int i,j;
for(int i=0; i<26; ++i)
scanf("%d",&val[i]);
scanf("%s",S);
int len=strlen(S);
memset(sum, 0, sizeof(sum));
sum[0]=val[S[0]-'a'];
for(i=1; i<len; ++i)
sum[i] = val[S[i]-'a']+sum[i-1];
strcpy(T,S);
strrev(T);
GetExtand(S,T,next1,extand1);
GetExtand(T,S,next2,extand2);
int Max=0;
for(i=1;i<len;i++)
{
now=0;
if(i+extand2[i]==len)
now+=sum[len-i-1];
if(len-i+extand1[len-i]==len)
now=now+sum[len-1]-sum[len-i-1];
if(now>Max) Max=now;
}
printf("%d\n",Max);
}
return 0;
}