摘要：
Unique Binary Search TreesGivenn, how many structurally uniqueBST's(binary search trees) that store values 1...n?For example,Givenn= 3, there are a to... 阅读全文
摘要：
AnagramsGiven an array of strings, return all groups of strings that are anagrams.Note: All inputs will be in lower-case.anagrams特点：单词里的字母的种类和数目是一样的，只... 阅读全文
摘要：
Valid NumberValidate if a given string is numeric.Some examples:"0"=>true" 0.1 "=>true"abc"=>false"1 a"=>false"2e10"=>trueNote:It is intended for the ... 阅读全文