摘要：
Given a string S and a string T, find the minimum window in S which will contain all the characters in T in complexity O(n). For example,S = "ADOBECOD 阅读全文
摘要：
Implement a trie with insert, search, and startsWith methods. Example: Note: You may assume that all inputs are consist of lowercase letters a-z. All 阅读全文
摘要：
Given a binary tree, return the level order traversal of its nodes' values. (ie, from left to right, level by level). For example:Given binary tree {3 阅读全文