Trie build and search class TrieNode { public: TrieNode * next[]; bool is_word; TrieNode(bool b = false) { memset(next,,sizeof(next)); is_word = b; } }; class Trie { TrieNode* root; public: /** Initialize your data structure here. */ Trie() { root =…

Implement a trie with insert, search, and startsWith methods. Note:You may assume that all inputs are consist of lowercase letters a-z. 实现一个字典树. 好久不做题,没感觉啊,TreeNode用一个布尔变量表示是否是一个合法单词的结尾即可,一开始还用cnt来计数,search的时候比较麻烦. class TrieNode { // Initialize your…

题目: Given a string s1, we may represent it as a binary tree by partitioning it to two non-empty substrings recursively. Below is one possible representation of s1 = "great": great / \ gr eat / \ / \ g r e at / \ a t To scramble the string, we ma…

原题链接: http://oj.leetcode.com/problems/scramble-string/  这道题看起来是比較复杂的,假设用brute force,每次做分割,然后递归求解,是一个非多项式的复杂度,一般来说这不是面试官想要的答案. 这事实上是一道三维动态规划的题目,我们提出维护量res[i][j][n],当中i是s1的起始字符,j是s2的起始字符,而n是当前的字符串长度,res[i][j][len]表示的是以i和j分别为s1和s2起点的长度为len的字符串是不是互为scram…

Implement a trie with insert, search, and startsWith methods. Note:You may assume that all inputs are consist of lowercase letters a-z. 思路:应该就是字典树. class TrieNode { public: TrieNode *dic[]; // Initialize your data structure here. TrieNode() { ; i < ;…

Question 438. Find All Anagrams in a String Solution 题目大意:给两个字符串,s和p,求p在s中出现的位置,p串中的字符无序,ab=ba 思路:起初想的是求p的全排列,保存到set中,遍历s,如果在set中出现,s中的第一个字符位置保存到结果中,最后返回结果.这种思路执行超时.可能是求全排列超时的. 思路2:先把p中的字符及字符出现的次数统计出来保存到map中,再遍历s,这个思路和169. Majority Element - LeetCode…

Given s1, s2, s3, find whether s3 is formed by the interleaving of s1 and s2. For example,Given:s1 = "aabcc",s2 = "dbbca", When s3 = "aadbbcbcac", return true.When s3 = "aadbbbaccc", return false. 定义boolean 数组result…

题目: Given s1, s2, s3, find whether s3 is formed by the interleaving of s1 and s2. For example, Given: s1 = "aabcc", s2 = "dbbca", When s3 = "aadbbcbcac", return true. When s3 = "aadbbbaccc", return false. 题解: 这道题还是像…

Given s1, s2, s3, find whether s3 is formed by the interleaving of s1 and s2. For example,Given:s1 = "aabcc",s2 = "dbbca", When s3 = "aadbbcbcac", return true.When s3 = "aadbbbaccc", return false. 题目大意:给定三个字符串,s1,s2…

思路:在原来的字符串后面添加上strlen-1个字符,返回 class Solution { public: string reverseString(string s) { unsigned int strlen; int i; // char temp; strlen = s.size(); ) { ; i >= ; i--) { // temp = s[i]; s += s[i]; } , strlen + strlen - ); } else return s; } };…