<题目链接> 题目大意: 给你一个字符串,要求将字符串的全部字符最少循环2次需要添加的字符数. [>>>kmp next函数 kmp的周期问题]  #include <cstdio> #include <cstring> + ; char s[maxn]; int Next[maxn]; void get_next() { , k = -; Next[] = -; while (s[j]) { || s[j] == s[k]) Next[++j] =…

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…

//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 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…

题目链接:HDU 3746 Sample Input 3 aaa abca abcde Sample Output 0 2 5 Author possessor WC Source HDU 3rd "Vegetable-Birds Cup" Programming Open Contest Solution 题意 给定一个字符串,问至少需要在末尾添加多少个字符使得字符串循环. 思路 KMP 设前缀函数为 \(\pi()\),字符串长度为 \(n\),下标从 \(1\) 开始. 最小循环…

思路: 这里只要注意一点,就是失配值和前后缀匹配值的区别,不懂的可以看看这里,这题因为对子串也要判定,所以用前后缀匹配值,其他的按照最小循环节做 代码: #include<iostream> #include<algorithm> const int N = 1000000+5; const int INF = 0x3f3f3f3f; using namespace std; int fail[N]; char p[N]; void getFail(){ fail[0] = -1;…

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…

题目地址:http://acm.hdu.edu.cn/showproblem.php?pid=3746 KMP算法—— AC代码: #include <iostream> #include <cstdio> #include <cstdlib> #include <cmath> #include <cstring> #include <string> #include <vector> #include <list&…

思路: 最小循环节的解释在这里,有人证明了那么就很好计算了 之前对KMP了解不是很深啊,就很容易做错,特别是对fail的理解 注意一下这里getFail的不同含义 代码: #include<iostream> #include<algorithm> const int N = 1000000+5; const int INF = 0x3f3f3f3f; using namespace std; int fail[N]; char p[N],t[N]; void getFail(){…

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…