KMP POJ 2406 Power Strings

题目传送门

 /*
     题意：一个串有字串重复n次产生，求最大的n
     KMP：nex[]的性质应用，感觉对nex加深了理解
 */
 /************************************************
 * Author        :Running_Time
 * Created Time  :2015-8-10 10:51:54
 * File Name     :POJ_2406.cpp
  ************************************************/

 #include <cstdio>
 #include <algorithm>
 #include <iostream>
 #include <sstream>
 #include <cstring>
 #include <cmath>
 #include <string>
 #include <vector>
 #include <queue>
 #include <deque>
 #include <stack>
 #include <list>
 #include <map>
 #include <set>
 #include <bitset>
 #include <cstdlib>
 #include <ctime>
 using namespace std;

 #define lson l, mid, rt << 1
 #define rson mid + 1, r, rt << 1 | 1
 typedef long long ll;
 const int MAXN = 1e6 + ;
 const int INF = 0x3f3f3f3f;
 const int MOD = 1e9 + ;
 char str[MAXN];
 int nex[MAXN];

 int get_nex(void)   {
     int len = strlen (str);
     int i = , j = -;  nex[] = -;
     while (i < len) {
         if (j == - || str[j] == str[i])    {
             j++;    i++;    nex[i] = j;
         }
         else    j = nex[j];
     }
     if (i % (i - nex[i]) == )  {
         return i / (i - nex[i]);
     }
     else    return ;
 }

 int main(void)    {     //POJ 2406 Power Strings
     while (scanf ("%s", str) == )  {
         if (str[] == '.')  break;
         printf ("%d\n", get_nex ());
     }

     return ;
 }