题意:目标串n( <= 10)个,病毒串m( < 1000)个,问包含所有目标串无病毒串的最小长度 思路:貌似是个简单的状压DP + AC自动机,但是发现dp[1 << n][5e4]根本开不出那么多空间,似乎GG.但是我们仔细想一下就能发现,既然要包含所有目标串的最小长度,那必然这个串就是只有目标串叠加组成的,只是在叠加的过程中我们不能混入病毒串.所以其实Trie树上有用的点最多就10个,我们只要处理出所有目标串之间"最小有效转化"就行了,那么空间为dp[1…

题目链接 Problem Description Dr. X is a biologist, who likes rabbits very much and can do everything for them. 2012 is coming, and Dr. X wants to take some rabbits to Noah's Ark, or there are no rabbits any more. A rabbit's genes can be expressed as a st…

\(\quad\)Great! Your new software is almost finished! The only thing left to do is archiving all your n resource files into a big one. \(\quad\)Wait a minute- you realized that it isn't as easy as you thought. Think about the virus killers. They'll f…

题意:给定 n 个文本串,m个病毒串,文本串重叠部分可以合并,但合并后不能含有病毒串,问所有文本串合并后最短多长. 析:先把所有的文本串和病毒都插入到AC自动机上,不过标记不一样,可以给病毒标记-1,如果访问知道就知道不可行的,然后处理出两两串叠加的最小长度,这个要用bfs,在AC自动机上把这个处理出来,然后剩下的就是一个简单的DP了,dp[s][i] 表示状态为 s 时,i 串在后面,长度最短是多少. 代码如下: #pragma comment(linker, "/STACK:10240000…

Resource Archiver Time Limit: 20000/10000 MS (Java/Others)    Memory Limit: 100000/100000 K (Java/Others)Total Submission(s): 2382    Accepted Submission(s): 750 Problem Description Great! Your new software is almost finished! The only thing left to…

Wireless Password Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 5640    Accepted Submission(s): 1785 Problem Description Liyuan lives in a old apartment. One day, he suddenly found that there…

题目链接 BZOJ1559 题解 考虑到这是一个包含子串的问题,而且子串非常少,我们考虑\(AC\)自动机上的状压\(dp\) 设\(f[i][j][s]\)表示长度为\(i\)的串,匹配到了\(AC\)自动机\(j\)号节点,且已匹配集合为\(s\)的方案数 直接在\(AC\)自动机上转移即可 但是为了防止使用\(last\)指针之类的,计算匹配的串,我们先将原串的集合去重和去包含关系 方案怎么办? 考虑到\(ans \le 42\),一定是刚好若干个原串以最长前后缀相同的方式相接 因为如果不…

Time Limit: 10 Seconds      Memory Limit: 65536 KB Dr. X is a biologist, who likes rabbits very much and can do everything for them. 2012 is coming, and Dr. X wants to take some rabbits to Noah's Ark, or there are no rabbits any more. A rabbit's gene…

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 5400    Accepted Submission(s): 1704 Problem Description Liyuan lives in a old apartment. One day, he suddenly found that there was a wireless ne…

题意:一张图,F是起点,Y是必须要到的点,D不能走,G可以充电.可以往四个方向走,每走一步花费一个电,走到G可以选择充满电或者不充,每个G只能充一次.问你走遍Y的最小初始点亮.number(G) + number(Y) <= 15 思路:显然Y和G都只要用一次就行,那么状压YG状态.然后BFS出任意YG两点最短路,状压DP.用&判断最终结果是不是当前状态的子集. 代码: #include<set> #include<map> #include<cmath>…

题目链接 Problem Description As we know, Rikka is poor at math. Yuta is worrying about this situation, so he gives Rikka some math tasks to practice. There is one of them: Yuta has n 01 strings si, and he wants to know the number of 01 antisymmetric stri…

http://acm.hdu.edu.cn/showproblem.php?pid=4057 题意:给出n个子串,串只包含‘A’,'C','G','T'四种字符,你现在需要构造出一个长度为l的串,如果这个串里面包含了某个子串,那么答案就会+val[i](如果这个串被使用过了,就不会再有贡献了),要使得构造出来的串的答案最大,问是多少. 思路:只能想到是AC自动机的题目,然后乱搞出一个错误的方法,没想到是这样的操作. n只有10,因此才1024,开一个dp[l][sz][st]的数组,l代表当前的…

题意:m个密码串,问你长度为n的至少含有k个不同密码串的密码有几个 思路:状压一下,在build的时候处理fail的时候要用 | 把所有的后缀都加上. 代码: #include<cmath> #include<set> #include<map> #include<queue> #include<cstdio> #include<vector> #include<cstring> #include <iostream…

给你m个字符串,让你构造一个字符串,包含所有的m个子串,问有多少种构造方法.如果答案不超过42,则按字典序输出所有可行解. 由于m很小,所以可以考虑状压. 首先对全部m个子串构造出AC自动机,每个节点有一个附加属性val[u]代表结点u包含的子串集合. 设dp[l][S][u]为长度为l,包含子串集合为S,当前在结点u时,接下来能构造出的合法字符串总数,则dp[l][S][u]=∑dp[l+1][S|val[v]][v],v=go[u][i],0<=i<26; 两遍dfs,一遍dp,一遍输出答…

传送门 题目大意: 给你一些密码片段字符串,让你求长度为n,且至少包含k个不同密码片段串的字符串的数量. 题解: 因为密码串不多,可以考虑状态压缩 设dp[i][j][sta]表示长为i的字符串匹配到j节点且状态为sta的数量. 其中sta存储的是包含的密码串情况,在构建fail指针时,当前节点要并上fail指针所指的节点. 跑ac自动机,儿子节点从父亲节点转移. 最后取dp[len][...][sta]的和,其中sta满足二进制中1的数量>=k, 这一点可以像树状数组的lowbit那样快速求出…

题目大概说有个n×m的格子,有两种走法,每种走法都是一个包含D或R的序列,D表示向下走R表示向右走.问从左上角走到右下角的走法有多少种走法包含那两种走法. D要走n次,R要走m次,容易想到用AC自动机上的DP解决: 用两种走法的序列构造AC自动机 dp[i][j][S][k]表示D用了i个R用了j个,且当前走到自动机的S结点,已经包含的走法的状态集合是k的方案数 转移就是走R或者走D了,我用我为人人来转移 #include<cstdio> #include<cstring> #in…

题目,求包含所有的给定的n个DNA片段的序列的最短长度. AC自动机上的DP题. dp[S][u]表示已经包含的DNA片段集合为S,且当前后缀状态是自动机第u个结点的最短长度 dp[0][0]=0 我为人人+队列轻松转移.. #include<cstdio> #include<cstring> #include<queue> #include<algorithm> using namespace std; #define INF (1<<30)…

Wireless Password Time Limit: 1000MS   Memory Limit: 32768KB   64bit IO Format: %I64d & %I64u Description Liyuan lives in a old apartment. One day, he suddenly found that there was a wireless network in the building. Liyuan did not know the password…

建AC自动机后, dp(x, y, s)表示当前长度为x, 在结点y, 包括的串的状态为s的方案数, 转移就在自动机上走就行了. 对于输出方案, 必定是由给出的串组成(因为<=42), 所以直接暴搜答案. 数据范围很小, 可以AC(复杂度懒得算了....) ------------------------------------------------------------------------------------------------ #include<cstdio> #in…

题目链接:hdu_2825_Wireless Password 题意: 给你m个串,问长度为n至少含k个串的字符串有多少个 题解: 设dp[i][j][k]表示考虑到长度为i,第j个自动机的节点,含有k这个压缩状态的方案数,然后DP下去就行了 #include<bits/stdc++.h> #define F(i,a,b) for(int i=a;i<=b;i++) using namespace std; ; *,tyn=;//数量乘串长,类型数 struct AC_automatio…

题目链接:https://vjudge.net/problem/HDU-2825 Wireless Password Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 7733    Accepted Submission(s): 2509 Problem Description Liyuan lives in a old apartmen…

题目连接:http://acm.hdu.edu.cn/showproblem.php?pid=2825 题意:给一些字符串,构造出长度为n的字符串,它至少包含k个所给字符串,求能构造出的个数. 题解: 对end[]节点标记数组进行改动,用二进制下第几位表示即为包含第几个给定子串: 状态转移方程为:dp[i+1][x][k|end[x]]=(dp[i+1][x][k|end[x]]+dp[i][j][k])%mod:(没懂为什么要用' | ' ,等搞明白了在更新吧,,) dp[i][j][l] 表…

Lost's revenge Time Limit: 5000MS Memory Limit: 65535KB 64bit IO Format: %I64d & %I64u Description Lost and AekdyCoin are friends. They always play "number game"(A boring game based on number theory) together. We all know that AekdyCoin is t…

题目大意:给一系列字符串,用小写字母构造出长度为n的至少包含k个字符串的字符串,求能构造出的个数. 题目分析:在AC自动机上走n步,至少经过k个单词节点,求有多少种走法. 代码如下: # include<iostream> # include<cstdio> # include<queue> # include<cstring> # include<algorithm> using namespace std; typedef long long…

题目大概是给几个DNA片段以及它们各自的权值,如果一个DNA包含某个片段那么它的价值就加上这个片段的权值,同时包含多个相同DNA片段也只加一次,问长度l的DNA可能的最大价值. 与HDU2825大同小异. dp[i][j][S]表示长度i(自动机转移i步).后缀状态为自动机第j个结点.包含的DNA片段为集合S 的DNA最大价值 dp[0][0][0]=0 我为人人转移,从dp[i][j][S]向ATCG四个方向更新dp[i+1][j'][S'] 注意的是要用滚动数组,不然要开上百兆数组. 用滚动…

题目问长度n至少包含k个咒语的字符串有多少个.也是比较入门的题.. dp[i][j][S]表示长度i(在自动机上转移k步)且后缀状态为自动机上第j个结点且当前包含咒语集合为S的方案数 dp[0][0][0]=1 还是用我为人人转移,AC自动机上的结点要多一个域表示这个结点所代表咒语前缀包含的咒语集合. #include<cstdio> #include<cstring> #include<queue> using namespace std; ][],fail[],fl…

Dr. X is a biologist, who likes rabbits very much and can do everything for them. 2012 is coming, and Dr. X wants to take some rabbits to Noah's Ark, or there are no rabbits any more. A rabbit's genes can be expressed as a string whose length is l (1…

Victor and World Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 262144/131072 K (Java/Others) Total Submission(s): 1463    Accepted Submission(s): 682 Problem Description After trying hard for many years, Victor has finally received a pilot…

BZOJ_3049_[Usaco2013 Jan]Island Travels _状压DP+BFS Description Farmer John has taken the cows to a vacation out on the ocean! The cows are living on N (1 <= N <= 15) islands, which are located on an R x C grid (1 <= R, C <= 50). An island is a…

题目链接:https://vjudge.net/problem/HDU-3247 Resource Archiver Time Limit: 20000/10000 MS (Java/Others)    Memory Limit: 100000/100000 K (Java/Others)Total Submission(s): 3228    Accepted Submission(s): 1052 Problem Description Great! Your new software i…