James Pan

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/regular-expression-matching/ Implement regular expression matching with support for '.' and '*'. '.' Matches any single character. '*' Matches zero or more of

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.