https://leetcode.com/problems/word-search/ class Solution { public: struct Trie{ Trie *next[]; bool isWord; Trie() { this->isWord = false; for(auto &c: next) c = NULL; } }; void insert(Trie *root, string word) { Trie *p = root; for(auto &c: wor…

字典树(查找树) 26个分支作用:检测字符串是否在这个字典里面插入.查找 字典树与哈希表的对比:时间复杂度:以字符来看:O(N).O(N) 以字符串来看:O(1).O(1)空间复杂度:字典树远远小于哈希表 前缀相关的题目字典树优于哈希表字典树可以查询abc是否有ab的前缀 字典树常考点:1.字典树实现2.利用字典树前缀特性解题3.矩阵类字符串一个一个字符深度遍历的问题(DFS+trie) dfs树和trie树同时遍历 word searchIIdfs+hash:时间复杂度大,后面遍历到有些字符就…

题目链接 写一个数据结构, 支持两种操作. 加入一个字符串, 查找一个字符串是否存在.查找的时候, '.'可以代表任意一个字符. 显然是Trie树, 添加就是正常的添加, 查找的时候只要dfs查找就可以. 具体dfs方法看代码. struct node { node *next[]; int idEnd; node() { memset(next, NULL, sizeof(next)); idEnd = ; } }; class WordDictionary { public: // Adds…

https://www.cnblogs.com/grandyang/p/4332313.html 在一个矩阵中能不能找到string的一条路径 这个题使用的是dfs.但这个题与number of islands有点不同,那个题中visited过的就不用再扫了,但是这个需要进行回溯回来. 所以使用了visited[i][j] = false; 本质区别还是那个题是找一片区域,这个题更像是找一条路径. 错误一:如果board不引用,会报超内存 错误二: 这个写法和正确写法基本相同,但错误写法需要每次…

题目链接:https://leetcode.com/problems/word-search/#/description 给出一个二维字符表,并给出一个String类型的单词,查找该单词是否出现在该二维字符表中. For example,Given board = [ ['A','B','C','E'], ['S','F','C','S'], ['A','D','E','E'] ] word = "ABCCED", -> returns true,word = "SEE…

Design a data structure that supports the following two operations: void addWord(word) bool search(word) search(word) can search a literal word or a regular expression string containing only letters a-z or .. A . means it can represent any one letter…

Given a 2D board and a word, find if the word exists in the grid. The word can be constructed from letters of sequentially adjacent cell, where "adjacent" cells are those horizontally or vertically neighboring. The same letter cell may not be us…

/** * Given a 2D board and a word, find if the word exists in the grid. The word can be constructed from letters of sequentially adjacent cell, where "adjacent" cells are those horizontally or vertically neighboring. The same letter cell may not…

Design a data structure that supports the following two operations: void addWord(word) bool search(word) search(word) can search a literal word or a regular expression string containing only letters a-z or .. A . means it can represent any one letter…

https://leetcode.com/problems/add-and-search-word-data-structure-design/ 本题是在Trie树进行dfs+backtracking操作. Trie树模板代码见:http://www.cnblogs.com/fu11211129/p/4952255.html 题目介绍: Design a data structure that supports the following two operations: void addWord…