HDU 3294 Girls' research

Posted 2020-08-13 BBBob

题目地址

manacher

 1 #include<cstdio>
 2 #include<string.h>
 3 #include<algorithm>
 4 using namespace std;
 5 const int Nmax=200005;
 6 char s[Nmax];
 7 char str[Nmax*2+10];
 8 int p[Nmax*2+10];
 9 int hashh[Nmax*2+10];
10 int id;
11 int maxlen;
12 int len;
13 int start;
14 int endd;
15 void init()
16 {
17     id=0;
18     maxlen=0;
19     int n=strlen(s);
20     str[0]=‘$‘;
21     str[1]=‘#‘;
22     for(int i=0;i<n;i++)
23     {
24         str[i*2+2]=s[i];
25         hashh[i*2+2]=i;
26         str[i*2+3]=‘#‘;
27     }
28     str[n*2+2]=‘&‘;
29     len=n*2+2;
30 }
31 
32 void get()
33 {
34     for(int i=2;i<len-2;i++)
35     {
36         if(id+p[id]>i)
37             p[i]=min(p[id*2-i],p[id]+id-i);
38         else
39             p[i]=1;
40         while(str[i-p[i]] == str[i+p[i]])
41             p[i]++;
42         if(p[i]+i>p[id]+id)
43             id=i;
44         if(p[i]>maxlen)
45         {
46             maxlen=p[i];
47             start=hashh[i-p[i]+2];
48             endd=hashh[i+p[i]-2];
49         }
50     }
51 }
52 
53 int main()
54 {
55     char c;
56     while(scanf("%c",&c)!=EOF)
57     {
58         //printf("c:%c\n",c);
59         getchar();
60         scanf("%s",s);
61         getchar();
62         init();
63         get();
64         if(maxlen-1>=2)
65         {
66             printf("%d %d\n",start,endd);
67             for(int i=start;i<=endd;i++)
68             {
69                 char k=(s[i]-c+26)%26+‘a‘;
70                 printf("%c",k);
71             }
72             printf("\n");
73         }
74         else
75             printf("No solution!\n");
76     }
77     return 0;
78 }