UVa455

455 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

题意：

       给出一个字符串，找出它的最大循环节字符串长度。

输入：

       情况数T，然后是一个空行，之后每一种情况给一个字符串，相邻两情况间有空行。

输出：

       每种情况输出它的最大循环节字符串长度。

分析：

       简单模拟，编写一个函数检验输入的字符串是否是某个长度的字符串的重复。然后列举输入字符串长度的所有因子，检查字符串是否是为某个因子长度的字符串的重复即可。

#include <cstdio>
#include <iostream>
#include <cstring>
#include <cmath>
using namespace std;
const int MAX_LEN = 80;
char str[90];
bool IS_THIS_STRING_LOOPING_IN_THIS_NUMBER(char str[],int loop_num,int len){
    for(int i = 0 ; i < loop_num ; i++)
        for(int j = i + loop_num ; j < len ; j += loop_num)
            if(str[i] != str[j]) return false;
    return true;
}
int main(){
    int T; cin >> T;
    while(T--){
        int ans;
        getchar();
        scanf("%s",str);
        int len = strlen(str);
        for(int i = 1 ; i <= len ; i++){
            if(len % i == 0){
                if(IS_THIS_STRING_LOOPING_IN_THIS_NUMBER(str,i,len)){
                    ans = i;
                    break;
                }
            }
        }
        printf("%d\n",ans);
        if(T != 0) cout << endl;
    }
    return 0;
}