POJ 2406 Power Strings(kmp)

题目链接

预处理改一下，就OK了。。。我竟然敲错模版了。。。3Y。一种是暴力，一种更巧妙。

直接取余判断

 1 #include <stdio.h>
 2 #include <string.h>
 3 #define N 1000001
 4 char str[N];
 5 int next[N];
 6 int main()
 7 {
 8     int i,j,len,d;
 9     while(scanf("%s",str)!=EOF)
10     {
11         if(str[0] == '.')break;
12         len = strlen(str);
13         next[0] = -1;
14         j = -1;
15         for(i = 1;i <= len-1;i ++)
16         {
17             while(j >= 0&&str[j+1] != str[i])
18             j = next[j];
19             if(str[j+1] == str[i]) j++;
20             next[i] = j;
21         }
22         d = len-1-next[len-1];
23         if(len % d == 0)//开始的时候没加，WA了，用暴力水过了
24         printf("%d\n",len/d);
25         else
26         printf("1\n");
27     }
28     return 0;
29 }

暴力

 1 #include <stdio.h>
 2 #include <string.h>
 3 #define N 1000001
 4 char str[N];
 5 int next[N];
 6 int main()
 7 {
 8     int i,j,len,num,d,z;
 9     while(gets(str)!=0)
10     {
11         memset(next,0,sizeof(next));
12         if(str[0] == '.')break;
13         len = strlen(str);
14         next[0] = -1;
15         j = -1;
16         num = 1;
17         for(i = 1;i <= len-1;i ++)
18         {
19             while(j >= 0&&str[j+1] != str[i])
20             j = next[j];
21             if(str[j+1] == str[i]) j++;
22             next[i] = j;
23         }
24         d = len-1-next[len-1];
25         if(d != len)
26         num ++;
27         z = 1;
28         for(i = next[len-1];;i -= d)
29         {
30             if(d == i-next[i]&&next[i] != -1)
31             {
32                 num ++;
33             }
34             else if(d == i+1&&next[i] == -1)
35             {
36                 break;
37             }
38             else
39             {
40                 z = 0;
41                 break;
42             }
43         }
44         if(z)
45         printf("%d\n",num);
46         else
47         printf("%d\n",1);
48     }
49     return 0;
50 }
posted @ 2012-07-20 11:08  Naix_x  阅读(165)  评论(0)  编辑  收藏  举报