題目： There are a total of n courses you have to take, labeled from 0 to n - 1. Some courses may hav ...

題目： Serialization is the process of converting a data structure or object into a sequence of bits s ...

題目： Given an array of meeting time intervals consisting of start and end times [[s1,e1],[s2,e2],... ...

題目： Given a binary search tree, write a function kthSmallest to find the kth smallest element in it ...

題目： Given a positive integer n, find the least number of perfect square numbers (for example, 1, 4, ...

題目： Given a binary tree, find the lowest common ancestor (LCA) of two given nodes in the tree. Acc ...

題目： Given a binary search tree (BST), find the lowest common ancestor (LCA) of two given nodes in t ...

題目： Given two words (beginWord and endWord), and a dictionary's word list, find the length of short ...