摘要：Question Given a collection of numbers that might contain duplicates, return all possible unique permutations. For example,[1,1,2] have the following 阅读全文

摘要：Question There are a total of n courses you have to take, labeled from 0 to n-1. Some courses may have prerequisites, for example to take course 0 you 阅读全文

摘要：Question 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: “ 阅读全文

摘要：Question Given a binary tree, determine if it is height-balanced. For this problem, a height-balanced binary tree is defined as: a binary tree in whic 阅读全文

摘要：Recursion is a technique in which a problem is solved by itself; it's a technique to solve most Divide & Conquer problems. Differences between Divide 阅读全文