[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…

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…

Given a binary tree, find the lowest common ancestor (LCA) of two given nodes in the tree. According to the definition of LCA on Wikipedia: “The lowest common ancestor is defined between two nodes v and w as the lowest node in T that has both v and w…

Given a binary search tree (BST), find the lowest common ancestor (LCA) of two given nodes in the BST. According to the definition of LCA on Wikipedia: “The lowest common ancestor is defined between two nodes v and w as the lowest node in T that has…

[题目] 输入二叉树中的两个结点,输出这两个结点在数中最低的共同父结点. 二叉树的结点定义如下:  C++ Code  123456   struct BinaryTreeNode {     int value;     BinaryTreeNode *left;     BinaryTreeNode *right; }; [分析] 求数中两个结点的最低共同结点是面试中经常出现的一个问题.这个问题有几个变种. [变种1] 第一个变种是二叉树是一种特殊的二叉树:查找二叉树.也就是树是排序过的,位…

Given a binary search tree (BST), find the lowest common ancestor (LCA) of two given nodes in the BST. According to the definition of LCA on Wikipedia: “The lowest common ancestor is defined between two nodes v and w as the lowest node in T that has…

题目如下:https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree/ Given a binary tree, find the lowest common ancestor (LCA) of two given nodes in the tree. According to the definition of LCA on Wikipedia: “The lowest common ancestor is def…

Given a binary search tree (BST), find the lowest common ancestor (LCA) of two given nodes in the BST. According to the definition of LCA on Wikipedia: “The lowest common ancestor is defined between two nodes v and w as the lowest node in T that has…

Given a binary tree, find the lowest common ancestor (LCA) of two given nodes in the tree. According to the definition of LCA on Wikipedia: “The lowest common ancestor is defined between two nodes v and w as the lowest node in T that has both v and w…

Given a binary search tree (BST), find the lowest common ancestor (LCA) of two given nodes in the BST. According to the definition of LCA on Wikipedia: "The lowest common ancestor is defined between two nodes v and w as the lowest node in T that has…