poj 2406 Power Srings (kmp循环节) (经典)

#include <cstdio>
#include <cstring>

const int maxn = 1000000 + 100;

char str[maxn];
int Next[maxn];

void get_next()
{
    int j = 0, k = -1;
    Next[0] = -1;
    while (str[j])
    {
        if (k == -1 || str[j] == str[k])
            Next[++j] = ++k;
        else
            k = Next[k];
    }
}

int main()
{
    while (scanf("%s", &str) != EOF)
    {
        if (str[0] == ‘.‘)break;
        get_next();
        int len = strlen(str);
        int length = len - Next[len];        //最小循环节
        
        if (len%length == 0)
        {
            printf("%d\n", len / length);
        }
        else
            printf("1\n");
    }
    return 0;
}