UVA455Periodic Strings(最小周期串)

Posted 2021-01-28 mlcn-2000

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

//原题链接https://vj.e949.cn/24c0d68c7b969c38f92f9f7f78cb2162?v=1545008735

//这道题的输入输出格式是真的一不小心就会错，全花时间在整格式上了=。=。总之这道题关键在于每个周期串长度相同，所以只需要找出最小的让v1和v2串

//相等的字符个数就行。这道题用string的毛串直接拼接效率会高点，代码如下。

#include <iostream>
#include <string>
using namespace std;
int main()
{
    string v1;
    int n;
    cin>>n;
    while(n--)
    {
        int i;
        cin>>v1;
        string k="";
        for(i=1;i<=v1.size();i++)
        {
            k+=v1[i-1];
            string v2="";
            for(int j=0;j<v1.size()/i;j++)
            v2+=k;
            if(v2==v1)
            break;
        }
        cout<<i<<endl;
        if(n)
        cout<<endl;
    }
    return 0;
}