UVa 455 Periodic Strings【最小循环子串】

A character string is said to have period k if it can be formed by concatenating one or more repetitions of another string of length k. For example, the string "abcabcabcabc" has period 3, since it is formed by 4 repetitions of the string "abc". It also has periods 6 (two repetitions of "abcabc") and 12 (one repetition of "abcabcabcabc").

Write a program to read a character string and determine its smallest period.

Input

The first line oif the input file will contain a single integer N indicating how many test case that your program will test followed by a blank line. Each test case will contain a single character string of up to 80 non-blank characters. Two consecutive input will separated by a blank line.

Output

An integer denoting the smallest period of the input string for each input.Two consecutive output are separated by a blank line.【结尾没有回车】

Sample Input

1HoHoHo

Sample Output

2

#include <stdio.h>#include <string.h>char str[105];int main(){int n,len,i,k;scanf("%d",&n);while(n--){memset(str,'\0',sizeof(str));scanf("%s",str); len=strlen(str);for(i=1;i<=len;i++){//该字符串可能没有循环字子串，那么就是他本身，i=len if(len%i==0)//最小子串一定是可以被len整除的 {for(k=i;k<len;k++){if(str[k]!=str[k%i])break;}if(k==len){printf("%d\n",i);break;}} }if(n)printf("\n");}return 0; }

注意比较巧妙的是

len%i==0   //最小子串一定是可以被len整除的

if(str[k]!=str[k%i])

下标从0开始，k从i开始依次与前i个字母进行比较