纪念卡常把自己卡死的一次自闭模拟赛 QWQ 一开始看这个题,以为是个图论,仔细一想,貌似可以直接dp啊. 首先,因为规则只有从两个变为1个,貌似可以用类似区间\(dp\)的方式来\(check\)一段区间能不能合成某一个字母! 那我们定义\(f[i][j][k]\)表示第一个串,\([l,r]\)区间,是否可以合成\(k\)这个字母 然后转移的时候,枚举区间,枚举规则,枚举断点,满足\(f[l][k][p1]==1\)且\(f[k+1][r][p2]==1\) 才能使当前状态合法. 其中\(p1…

1143 Lowest Common Ancestor(30 分)The lowest common ancestor (LCA) of two nodes U and V in a tree is the deepest node that has both U and V as descendants. A binary search tree (BST) is recursively defined as a binary tree which has the following prop…

[CF49E]Common ancestor 题目大意: 有两个由小写字母构成的字符串\(S\)和\(T(|S|,|T|\le50)\).另有\(n(n\le50)\)个形如\(a\to bc\)的信息,表示可以将字符\(a\)替换为\(bc\).定义两个字符串\(s,T\)的祖先\(R\)为能够通过若干次替换,使得其既可以变为\(S\),又可以变为\(T\)的字符串.求\(|R|\)的最小值. 思路: 首先分别预处理\(S,T\)中每一段是否可以通过单个字符转化过来,如果能,可以从哪些字符开始…

[Aizu2292]Common Palindromes(回文树) 题面 Vjudge 神TMD日语 翻译: 给定两个字符串\(S,T\),询问\((i,j,k,l)\)这样的四元组个数 满足\(S[i,j],T[k,l]\)都是回文串并且\(S[i,j]=T[k,l]\) 题解 自己\(yy\)一下就会做了 回文树又叫做回文自动机,所以当然可以用来进行回文串的识别和匹配了 对于一个串构建\(PAM\)或者说回文树,统计一下每个回文串的出现次数 再用另外一个串在\(PAM\)上进行匹配,计算一下…

The lowest common ancestor (LCA) of two nodes U and V in a tree is the deepest node that has both U and V as descendants. A binary search tree (BST) is recursively defined as a binary tree which has the following properties: The left subtree of a nod…

Common Substrings Description A substring of a string T is defined as: T(i, k)=TiTi+1...Ti+k-1, 1≤i≤i+k-1≤|T|. Given two strings A, B and one integer K, we define S, a set of triples (i, j, k): S = {(i, j, k) | k≥K, A(i, k)=B(j, k)}. You are to give…

传送门 Nearest Common Ancestors Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 26612   Accepted: 13734 Description A rooted tree is a well-known data structure in computer science and engineering. An example is shown below:    In the figur…

1145 Hashing - Average Search Time(25 分)The task of this problem is simple: insert a sequence of distinct positive integers into a hash table first. Then try to find another sequence of integer keys from the table and output the average search time (…

题目描述 给定一棵二叉树, 找到该树中两个指定节点的最近公共祖先. 百度百科中最近公共祖先的定义: “对于有根树T的两个结点u.v,最近公共祖先表示一个结点x,满足x是u.v的祖先且x的深度尽可能大.”(一个节点也可以是它自己的祖先) _______3______ / \ ___5__ ___1__ / \ / \ 6 _2 0 8 / \ 7 4 例如,节点5和节点1的最近公共祖先是节点3:节点5和节点4的最近公共祖先是节点5,因为根据定义,一个节点可以是它自己的祖先. 解题思路 考虑用前序遍…

Description Partychen like to do mathematical problems. One day, when he was doing on a least common multiple(LCM) problem, he suddenly thought of a very interesting question: if given a number of S, and we divided S into some numbers , then what is…