Power Strings
Time Limit: 3000MS |
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Memory Limit: 65536K |
Total Submissions: 16472 |
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Accepted: 6863 |
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).
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
Hint
This problem has huge input, use scanf instead of cin to avoid time limit exceed.
#include <iostream> #include <stdio.h> #include <string.h> #include <algorithm> #include <string> using namespace std; char s[1111111]; int next[1111111]; void getnext(int x){ int i=0,j=-1; next[0]=-1; while(i<x){ if(j==-1||s[i]==s[j]){ i++;j++; if(s[i]==s[j]) next[i]=next[j]; else next[i]=j; } else j=next[j]; } } int main() { int x; while(scanf("%s",s),s[0]!='.'){ x=strlen(s); int len; getnext(x); //能整除就重复了 x/(x-next[x]) 次 //不能整除就是它本身 if(x%(x-next[x])!=0) len=1; else len=x/(x-next[x]); printf("%d/n",len); } }