joj 1873 Power Strings

 1873: Power Strings

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Result	TIME Limit	MEMORY Limit	Run Times	AC Times	JUDGE
	10s	8192K	650	258	Standard

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).

Each test case is a line of input representing s, a string of printable characters. For each s you should print the largest n such that s = a^n for some string a. 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.

Sample Input

abcd
aaaa
ababab
.

Output for Sample Input

1
4
3

 

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This problem is used for contest: 73 

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一个基础的周期串问题。

有更好的办法，不过还是很黄很暴力的枚举吧（大爱各种暴力流水流）...

不过这样写真心跑得很慢...

 

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

int main()
{
    char s[1000005];
    int n;
    int i, j;
    
    //freopen("in.txt", "r", stdin);
    
    while (scanf("%s", s) == 1, s[0] != '.')
    {
        n = strlen(s);
        
        for (i=1; i<=n; ++i)
        {
            if (0 == n % i)
            {
                int ok = 1;
                for (j=i; j<n; ++j)
                {
                    if (s[j] != s[j%i])
                    {
                        ok = 0;
                        break;
                    }
                }
                if (ok)
                {
                    printf("%d\n", n/i);
                    break;
                }
            }
        }
    }
    
    
    return 0;
}