Power Strings
Description
Given two strings a and b we define a*b to be their concatenation. For example, if a = "abc" and b = "def" then a*b = "abcdef". If we think of concatenation as multiplication, exponentiation by a non-negative integer is defined in the normal way: a^0 = "" (the
empty string) and a^(n+1) = a*(a^n).
empty string) and a^(n+1) = a*(a^n).
Input
Each test case is a line of input representing s, a string of printable characters. The length of s will be at least 1 and will not exceed 1 million characters. A line containing a period follows the last test case.
Output
For each s you should print the largest n such that s = a^n for some string a.
Sample Input
abcd aaaa ababab .
Sample Output
1 4 3
题解：kmp求循环节。
#include<cstdio>
#include<cstring>
using namespace std;
char s[1000005];
int next[1000005];
int get_next(int l)
{
int i=0,j=-1;
next[0]=-1;
for(;s[i];)
if(j==-1||s[i]==s[j])
{
++i;++j;next[i]=j;
}
else j=next[j];
int x=l-next[l];
if(l%x==0)
return l/x;
return 1;
}
int main()
{
for(;scanf("%s",s);)
{
int len=strlen(s);
if(s[0]=='.') break;
printf("%d\n",get_next(len));
}
return 0;
}