HDU 3746 Cyclic Nacklace KMP

 1 // File Name: getnext.cpp
 2 // Author: darkdream
 3 // Created Time: 2014年09月09日 星期二 22时35分02秒
 4 
 5 #include<vector>
 6 #include<list>
 7 #include<map>
 8 #include<set>
 9 #include<deque>
10 #include<stack>
11 #include<bitset>
12 #include<algorithm>
13 #include<functional>
14 #include<numeric>
15 #include<utility>
16 #include<sstream>
17 #include<iostream>
18 #include<iomanip>
19 #include<cstdio>
20 #include<cmath>
21 #include<cstdlib>
22 #include<cstring>
23 #include<ctime>
24 #define LL long long
25 
26 using namespace std;
27 char str[300004];
28 int next[300005];
29 void getnext()
30 {
31     int len = strlen(str);
32     next[0] = -1; 
33     int k = -1;
34     int j = 0 ;
35     int sum = 0 ; 
36     while(j <= len - 1)
37     {
38         if(k == -1 || str[j] == str[k])
39         {
40             ++j; 
41             ++k;
42             next[j] = k ;
43         }
44         else {
45             k = next[k];
46         }
47     }
48 /*    for(int i = 0 ;i <= len; i ++)
49         printf("%d ",next[i]);
50     printf("\n");*/
51     int t = len - next[len];
52     if(next[len]%t == 0 && len/t != 1)
53     {
54         printf("0\n");
55     }else{
56         printf("%d\n",((next[len]/t+1) * t -next[len]));
57     }
58 
59 }
60 int main(){
61     int t; 
62     scanf("%d",&t);
63     while(t--)
64     {
65         scanf("%s",str);
66         getnext();
67     }
68     return 0;
69 }