HDU 3613 扩展KMP

暴力枚举大水题，判断回文，扩展KMP

#include <cstdio>
#include <cstring>
#include <algorithm>

using namespace std;

const int maxn = ;

int a[];
char str[];
char str1[];
int s[];

int _next[maxn],_extend[maxn];
int next1[maxn],extend1[maxn];

void getnext(char *T) {
    int a = ;
    int Tlen = strlen(T);
    _next[] = Tlen;
    while(a<Tlen-&&T[a]==T[a+]) a++;
    _next[] = a;

    a = ;
    for(int k=; k < Tlen; k++) {
        int p = a + _next[a] - ,L = _next[k-a];
        if((k-)+L>=p) {
            int j = (p-k+) >  ? p - k +  : ;
            while(k+j<Tlen&&T[k+j]==T[j])
                j++;
            _next[k] = j;
            a = k;
        }
        else _next[k] = L;
    }
}

void getextend(char *S,char *T) {
    int a = ;
    getnext(T);

    int Slen = strlen(S);
    int Tlen = strlen(T);

    int Minlen = Slen < Tlen ? Slen : Tlen;
    while(a<Minlen&&S[a]==T[a]) a++;
    _extend[] = a;
    a = ;

    for(int k = ; k < Slen; k++) {
        int p = a + _extend[a] - ,L = _next[k-a];
        if((k-)+L>=p) {
            int j = (p-k+) >  ? p - k +  : ;
            while(k+j<Slen&&j<Tlen&&S[k+j]==T[j]) j++;
            _extend[k] = j;
            a = k;
        }
        else
            _extend[k] = L;
    }

}

void getnext1(char *T) {
    int a = ;
    int Tlen = strlen(T);
    next1[] = Tlen;
    while(a<Tlen-&&T[a]==T[a+]) a++;
    next1[] = a;

    a = ;
    for(int k=; k < Tlen; k++) {
        int p = a + next1[a] - ,L = next1[k-a];
        if((k-)+L>=p) {
            int j = (p-k+) >  ? p - k +  : ;
            while(k+j<Tlen&&T[k+j]==T[j])
                j++;
            next1[k] = j;
            a = k;
        }
        else next1[k] = L;
    }
}

void getextend1(char *S,char *T) {
    int a = ;
    getnext1(T);

    int Slen = strlen(S);
    int Tlen = strlen(T);

    int Minlen = Slen < Tlen ? Slen : Tlen;
    while(a<Minlen&&S[a]==T[a]) a++;
    extend1[] = a;
    a = ;

    for(int k = ; k < Slen; k++) {
        int p = a + extend1[a] - ,L = next1[k-a];
        if((k-)+L>=p) {
            int j = (p-k+) >  ? p - k +  : ;
            while(k+j<Slen&&j<Tlen&&S[k+j]==T[j]) j++;
            extend1[k] = j;
            a = k;
        }
        else
            extend1[k] = L;
    }

}

int main() {
    int T;
    scanf("%d",&T);
    while(T--) {

        for(int i = ; i < ; i++)
            scanf("%d",&a[i]);

        scanf("%s",str);

        int len = strlen(str);

        s[] = a[ str[] - 'a' ];
        for(int i = ; i < len; i++)
            s[i] = s[i-] + a[ str[i]-'a' ];

        for(int i = ; i < len; i++)
            str1[i] = str[len-i-];

        getextend(str1,str);
        getextend1(str,str1);

        int ans = ;
        for(int i = ; i < len-; i++)
        {
            if(_extend[len-i-]==i+&&extend1[i+]==len-i-)
                ans = max(ans,s[len-]);
            else if(_extend[len-i-]==i+)
                ans = max(ans,s[i]);
            else if(extend1[i+]==len-i-)
                ans = max(ans,s[len-]-s[i]);
        }

        printf("%d\n",ans);
    }
    return ;
}