POJ 1961 Period（KMP)

题目链接

和POJ2406差不多，不过用暴力去找，会超时。

 1 #include <stdio.h>

 2 #include <string.h>

 3 #include <math.h>

 4 #define N 1000001

 5 char str[N];

 6 int next[N];

 7 int main()

 8 {

 9     int i,j,len,d,a = 0;

10     while(scanf("%d%*c",&len)!=EOF)

11     {

12         a ++;

13         if(len == 0)break;

14         scanf("%s",str);

15         memset(next,0,sizeof(next));

16         if(str[0] == '.')break;

17         next[0] = -1;

18         j = -1;

19         for(i = 1; i <= len-1; i ++)

20         {

21             while(j >= 0&&str[j+1] != str[i])

22                 j = next[j];

23             if(str[j+1] == str[i]) j++;

24             next[i] = j;

25         }

26         printf("Test case #%d\n",a);

27         for(j = 1; j <= len; j ++)

28         {

29             d = j-1-next[j-1];

30             if(j % d == 0&&j/d != 1)

31             printf("%d %d\n",j,j/d);

32         }

33         printf("\n");

34     }

35     return 0;

36 }