James Pan

原题网址：https://leetcode.com/problems/binary-search-tree-iterator/ Implement an iterator over a binary search tree (BST). Your iterator will be initialized with the root node of a BST. Calling ne

原题网址：https://leetcode.com/problems/serialize-and-deserialize-binary-tree/ Serialization is the process of converting a data structure or object into a sequence of bits so that it can be stored in

原题网址：https://leetcode.com/problems/flatten-nested-list-iterator/ Given a nested list of integers, implement an iterator to flatten it. Each element is either an integer, or a list -- whose ele

原题网址：https://leetcode.com/problems/flatten-2d-vector/ Implement an iterator to flatten a 2d vector. For example, Given 2d vector = [ [1,2], [3], [4,5,6] ] By calling next repea

原题网址：https://leetcode.com/problems/string-to-integer-atoi/ Implement atoi to convert a string to an integer. Hint: Carefully consider all possible input cases. If you want a challenge, please

原题网址：https://leetcode.com/problems/roman-to-integer/ Given a roman numeral, convert it to an integer. Input is guaranteed to be within the range from 1 to 3999. 方法：理解罗马数字。 public class Solut

原题网址：https://leetcode.com/problems/simplify-path/ Given an absolute path for a file (Unix-style), simplify it. For example, path = "/home/", => "/home" path = "/a/./b/../../c/", => "/c"

原题网址：https://leetcode.com/problems/valid-number/ Validate if a given string is numeric. Some examples: "0" => true " 0.1 " => true "abc" => false "1 a" => false "2e10" => true Note:

原题网址：https://leetcode.com/problems/length-of-last-word/ Given a string s consists of upper/lower-case alphabets and empty space characters ' ', return the length of last word in the string.