KMP + 求最小循环节 --- HUST 1010 - The Minimum Length

The Minimum Length 

Problem's Link:  http://acm.hust.edu.cn/problem/show/1010

---

 

Mean: 

给你一个字符串，求这个字符串的最小循环节。

analyse:

KMP之next数组的运用。裸的求最小循环节。

Time complexity: O(N)

 

Source code: 

/*
* this code is made by crazyacking
* Verdict: Accepted
* Submission Date: 2015-07-28-07.12
* Time: 0MS
* Memory: 137KB
*/
#include <queue>
#include <cstdio>
#include <set>
#include <string>
#include <stack>
#include <cmath>
#include <climits>
#include <map>
#include <cstdlib>
#include <iostream>
#include <vector>
#include <algorithm>
#include <cstring>
#define  LL long long
#define  ULL unsigned long long
using namespace std;
const int MAXN = 1000010;
int n;
char s [ MAXN ];
int Next [ MAXN ];
void getNext()
{
      Next [ 0 ] = 0; f
      for( int i = 1 , k = 0; i <n; ++ i)
      {
            while(s [ i ] !=s [ k ] && k) k = Next [ k - 1 ];
            if(s [ i ] ==s [ k ]) ++ k;
            Next [ i ] = k;
      }
}
int main()
{
      ios_base :: sync_with_stdio( false);
      cin . tie( 0);
      while( ~ scanf( "%s" ,s))
      {
           n = strlen(s);
            getNext();
            int min_cycle =n - Next [n - 1 ];
            printf( "%d \n " , min_cycle);
      }
      return 0;
}
/*

*/