hdu 3613 扩展kmp+回文串

  1 #include<cstdio>
  2 #include<iostream>
  3 #include<algorithm>
  4 #include<cstring>
  5 #include<cmath>
  6 #include<queue>
  7 #include<map>
  8 using namespace std;
  9 #define MOD 1000000007
 10 const int INF=0x3f3f3f3f;
 11 const double eps=1e-5;
 12 #define cl(a) memset(a,0,sizeof(a))
 13 #define ts printf("*****\n");
 14 const int MAXN=500005;
 15 int n,m,tt;
 16 char s1[MAXN],s2[MAXN];
 17 int v[29],sum[MAXN];
 18 void pre_EKMP(char x[],int m,int nextt[])
 19 {
 20     nextt[0]=m;
 21     int j=0;
 22     while(j+1<m && x[j]==x[j+1])j++;
 23     nextt[1]=j;
 24     int k=1;
 25     for(int i=2;i<m;i++)
 26     {
 27         int p=nextt[k]+k-1;
 28         int L=nextt[i-k];
 29         if(i+L<p+1)nextt[i]=L;
 30         else
 31         {
 32             j=max(0,p-i+1);
 33             while(i+j<m && x[i+j]==x[j])j++;
 34             nextt[i]=j;
 35             k=i;
 36         }
 37     }
 38 }
 39 void EKMP(char x[],int m,char y[],int n,int nextt[],int extend[])
 40 {
 41     pre_EKMP(x,m,nextt);
 42     int j=0;
 43     while(j<n && j<m && x[j]==y[j])j++;
 44     extend[0]=j;
 45     int k=0;
 46     for(int i=1;i<n;i++)
 47     {
 48         int p=extend[k]+k-1;
 49         int L=nextt[i-k];
 50         if(i+L<p+1)extend[i]=L;
 51         else
 52         {
 53             j=max(0,p-i+1);
 54             while(i+j<n && j<m && y[i+j]==x[j])j++;
 55             extend[i]=j;
 56             k=i;
 57         }
 58     }
 59 }
 60 int nextt[MAXN],extend1[MAXN],extend2[MAXN];
 61 int main()
 62 {
 63     int i,j,k;
 64     #ifndef ONLINE_JUDGE
 65     freopen("1.in","r",stdin);
 66     #endif
 67     scanf("%d",&tt);
 68     while(tt--)
 69     {
 70         for(i=0;i<26;i++)
 71         {
 72             scanf("%d",&v[i]);
 73         }
 74         scanf("%s",s1);
 75         int len=strlen(s1);
 76         for(i=0;i<len;i++)
 77         {
 78             sum[i+1]=v[s1[i]-‘a‘]+sum[i];
 79         }
 80         strcpy(s2,s1);
 81         strrev(s2);
 82         EKMP(s2,len,s1,len,nextt,extend1);
 83         EKMP(s1,len,s2,len,nextt,extend2);
 84         int maxx=0;
 85         for(i=1;i<len;i++)  //枚举断点
 86         {
 87             int tot=0;
 88             if(i+extend1[i]==len)   //这里求的是断点后面的
 89             {
 90                 tot+=sum[len]-sum[i];
 91             }
 92             int ll=len-i;
 93             if(ll+extend2[ll]==len)
 94             {
 95                 tot+=sum[len]-sum[ll];
 96             }
 97             maxx=max(maxx,tot);
 98         }
 99         printf("%d\n",maxx);
100     }
101 }