枚举-Periodic Strings

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.

Sample Input
1
HoHoHo

Sample Output
2

题目大意：给出一个字符串，这个字符串是由很多个子字符串重复组成的，找出这子字符串

思路：从1到字符串的长度一个一个枚举即可，判断第l[j]是否跟在它前面i位的字符相等，由于在她前面i位上的字符跟l[j%i]相等，所以判断跟l[j%i]是否相等即可

代码：

#include<stdio.h>
#include<string.h>

int n,i,j,len;

int main(void)
{
    scanf("%d",&n);
    while(n--)
    {
        char l[100];
        scanf("%s",l);
        len=strlen(l);
        for(i=1;i<=len;i++)
        {
            if(len%i==0)//这里进行剪枝，子序列的长度一定能被序列长度整除
            {
                for(j=i;j<len;j++)
                {
                    if(l[j]!=l[j%i])//这句话的意思就是l[j]位上是否等于在它前i位上的字符
                        break;
                }
                if(j==len)
                {
                    printf("%d\n",i);
                    break;
                }
            }
        }
        if(n)
            printf("\n");
    }
    return 0;
}