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…

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…

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…

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…

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…

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…

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…

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…