题意:给出一段字符串  求最少在最右边补上多少个字符使得形成循环串(单个字符不是循环串) 自己乱搞居然搞出来了... 想法是:  如果nex[len]为0  那么答案显然是补len 否则  答案为循环节的长度-nex[len] 小于0变0 写了一个假算法居然能过    ... ababca就错了 kmp重要性质: 重要的性质len-next[i]为此字符串的最小循环节(i为字符串的结尾),另外如果len%(len-next[i])==0,此字符串的最小周期就为len/(len-next[i]);…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=3746 给你一个字符串,让你在后面加尽量少的字符,使得这个字符串成为一个重复串. abca---添加bc,成为abcabc abcd---添加abcd,成为abcdabcd aa---无需添加 经典的求最小循环节. 首先给出结论:一个字符串的最小循环节为:len-next[len] #include<stdio.h> #include<iostream> #include<algo…

题意: 给一个字符串,问:要补多少个字符才能让其出现循环?出现循环是指循环节与字符串长度不相等.比如abc要补多个变成abcabc.若已经循环,输出0. 思路: 根据最小循环节的公式,当len%(len-next[len])==0时,最小循环节为len/(len-next[len]),而当len%(len-next[len])!=0时,就没有循环节.可以通过在串尾补上一些字符,使得len%(len-next[len])==0,就会出现循环节了. #include <bits/stdc++.h>…

Cyclic Nacklace Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 1946    Accepted Submission(s): 854 Problem Description CC always becomes very depressed at the end of this month, he has checked…

https://vjudge.net/problem/UVA-1328 题意 求每个前缀的最小循环节,要求至少循环两次且为完整的. 分析 求next数组,i-next[i]即为前缀i的最小循环节,再判断一下限制条件即可. #include <iostream> #include <cstdio> #include <cstdlib> #include <cstring> #include <string> #include <algorit…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=1358 题意 :求给你个串,前i位子串由某个字符串重复k次得到,求所有的i和k(k>1); 例如: aabaabaabaab 前2个字符由2个a构成: 前6个字符由2个aab构成: 前9个字符由3个aab构成: 前12个字符由4个aab构成: #include<stdio.h> #include<iostream> #include<algorithm> #includ…

题目大意 给出字符串,寻找最小要补全的字符个数,使得字符串是两次的循环 解法 通过寻找规律,我们又发现了len-next[len]又派上了用场 ①如果next[len]是0,说明最大前缀后缀和为0,那么这个串里面没有什么重复的那种部分,也就是输出len例如abcde ②如果len%(len-next[len])==0也就是说里面已经具有这种重复两次的串了,所以输出0,例如aaa ③如果上述情况都不是,那么说明这个串里面包含重复部分但是不全.那么输出的公式是(len-next[len[)-len%…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=3746 题意:问在一个字符串末尾加上多少个字符能使得这的字符串首尾相连后能够循环 题解:就是利用next的性质求最小循环节 kmp求最下循环节http://www.cnblogs.com/wuyiqi/archive/2012/01/06/2314078.html ans=len-next[len];ans就是最小循环节长度证明看那个博客. 然后就简单了. #include <iostream> #…

KMP算法: 一:next数组:next[i]就是前面长度为i的字符串前缀和后缀相等的最大长度,也即索引为i的字符失配时的前缀函数. 二:KMP模板 /* pku3461(Oulipo), hdu1711(Number Sequence) 这个模板 字符串是从0开始的 Next数组是从1开始的 */ #include <iostream> #include <cstring> using namespace std; ; int _next[maxn]; char S[maxn],…

题目链接:https://vjudge.net/problem/HDU-3746 Cyclic Nacklace Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 10985    Accepted Submission(s): 4692 Problem Description CC always becomes very depresse…

题目链接:https://cn.vjudge.net/problem/HDU-3746 题意 给一串珠子,我们可以在珠子的最右端或最左端加一些珠子 问做一条包含循环珠子的项链,最少还需要多少珠子 思路 KMP的另一个用法,求最小循环节minloop=len-fail[len] 用我的观点来看KMP的fail数组,就是值域和定义域都是串的长度,返回值是这个串能够匹配后缀的最大前缀串长度 但是纯循环节构成的串中,这个返回值不包括第一个循环节 比如aabaabaab fail[9]==6 fail[6…

Cyclic Nacklace Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 16307    Accepted Submission(s): 6753 Problem Description CC always becomes very depressed at the end of this month, he has checke…

Problem Description CC always becomes very depressed at the end of this month, he has checked his credit card yesterday, without any surprise, there are only 99.9 yuan left. he is too distressed and thinking about how to tide over the last days. Bein…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=3746 Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others) Problem Description CC always becomes very depressed at the end of this month, he has checked his credit card yesterd…

https://www.bnuoj.com/v3/contest_show.php?cid=9147#problem/F [题意] 给定一个字符串,问在字符串后最少添加多少个字母,得到的新字符串能是前缀循环的字符串. [思路] 这道题的关键是要理解KMP中的nxt数组什么含义. nxt[i]就是以i结尾的字符串中前缀和后缀匹配的最长长度. 所以len-nxt[len]就是最小循环节. 如abcdab,nxt[len]就是2,最小循环节就是4(abcd). 理解了这个这道题就迎刃而解了. [网上解…

Cyclic Nacklace HDU 3746 KMP 循环节 题意 给你一个字符串,然后在字符串的末尾添加最少的字符,使这个字符串经过首尾链接后是一个由循环节构成的环. 解题思路 next[len]-len的差即是循环部分的长度. 这个是重点.这个题目自己开始没有想明白,看的博客,推荐这个. 代码实现 #include<cstdio> #include<cstring> #include<algorithm> using namespace std; const i…

Cyclic Nacklace 题意:给一个长度为Len( 3 <= Len <= 100000 )的英文串,问你在字符串后面最少添加几个字符可以使得添加后的串为周期串? Sample Input 3 aaa abca abcde   Sample Output 0 2 5   思路:要是写过period再来写这道题会发现很简单:就是在getfail()得到f[]之后,贪心地看最后一个字符所能用到的最长后缀长度为多少?而这个后缀长度就是n - n%len;(n为字符串长度,len为循环节的长度…

Cyclic Nacklace Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 13790    Accepted Submission(s): 5738 Problem Description CC always becomes very depressed at the end of this month, he has check…

Cyclic Nacklace Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 11516    Accepted Submission(s): 4913 Problem Description CC always becomes very depressed at the end of this month, he has checke…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=2087 题目大意:给你一个字符串,求出将字符串的最少出现两次循环节需要添加的字符数. 解题思路: 这题需要利用next数组的性质,求出字符串的最小循环节 有几个结论(具体可以看这里http://www.cnblogs.com/wuyiqi/archive/2012/01/06/2314078.html): ①字符串长度为len,则len-next[len]为最小循环节. ②如果len%(len-nex…

//len-next[len]为最小循环节的长度 # include <stdio.h> # include <algorithm> # include <string.h> using namespace std; int len; char a[100010]; int next[100010]; void Getnext() { int i=0,j=-1; next[0]=-1; while(i<=len) { if(j==-1||a[i]==a[j]) i…

Cyclic Nacklace Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 15422 Accepted Submission(s): 6425 Problem Description CC always becomes very depressed at the end of this month, he has checked his…

CC always becomes very depressed at the end of this month, he has checked his credit card yesterday, without any surprise, there are only 99.9 yuan left. he is too distressed and thinking about how to tide over the last days. Being inspired by the en…

CC always becomes very depressed at the end of this month, he has checked his credit card yesterday, without any surprise, there are only 99.9 yuan left. he is too distressed and thinking about how to tide over the last days. Being inspired by the en…

题目大意:给你一些串,问如果想让这个串里面的循环节至少循环两次,需要添加几个字符(只能在最前面或者最后面添加).比如ababc 需要添加5个就是添加ababc. 分析:其实字符串的长度len-next[len] = 最小循环节长度,为什么?其实也是需要对next的深刻了解,首先我们都知道next是求的最大的前缀和后缀的匹配度比如下面的字符串 ABCABCABC,很直接的就可以看出来最大的匹配串是ABCABC,但怎么从这个看出来最小的循环节呢?我们看到这个串的后缀串是从第4个字符开始的,也就是说从…

Cyclic Nacklace Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 2716    Accepted Submission(s): 1244 Problem Description CC always becomes very depressed at the end of this month, he has checked…

Cyclic Nacklace Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 2538    Accepted Submission(s): 1154 Problem Description CC always becomes very depressed at the end of this month, he has checke…

Cyclic Nacklace Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 4735    Accepted Submission(s): 2165 Problem Description CC always becomes very depressed at the end of this month, he has checked…

题意:给出一串字符串,可以在字符串的开头的结尾添加字符,求添加最少的字符,使这个字符串是循环的(例如:abcab 在结尾添加1个c变为 abcabc 既可). 思路:求出最小循环节,看总长能不能整除. #include<iostream> #include<stdio.h> #include<string.h> using namespace std; #define MaxSize 100005 int _next[MaxSize]; void GetNext(cha…

hdu3746 Cyclic Nacklace Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 2262    Accepted Submission(s): 1005 Problem Description CC always becomes very depressed at the end of this month, he ha…