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摘要： Given a binary tree, return thepreordertraversal of its nodes' values.For example:Given binary tree{1,#,2,3}, 1 \ 2 / 3return[1,2,3].Not... 阅读全文

摘要： Given a binary tree, return theinordertraversal of its nodes' values.For example:Given binary tree{1,#,2,3}, 1 \ 2 / 3return[1,3,2].Note... 阅读全文

摘要： Given a string containing just the characters'('and')', find the length of the longest valid (well-formed) parentheses substring.For"(()", the longest... 阅读全文

摘要： Given two numbers represented as strings, return multiplication of the numbers as a string.Note: The numbers can be arbitrarily large and are non-nega... 阅读全文

摘要： You are climbing a stair case. It takesnsteps to reach to the top.Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb... 阅读全文

摘要： Implement regular expression matching with support for'.'and'*'.'.' Matches any single character.'*' Matches zero or more of the preceding element.The... 阅读全文

摘要： Given a string containing only digits, restore it by returning all possible valid IP address combinations.For example:Given"25525511135",return["255.2... 阅读全文

摘要： Given a roman numeral, convert it to an integer.Input is guaranteed to be within the range from 1 to 3999.分析：首先我们熟悉下Roman数字组成规则：罗马数字一共有7个符号，'I':1, 'V'... 阅读全文

摘要： Given a strings1, we may represent it as a binary tree by partitioning it to two non-empty substrings recursively.Below is one possible representation... 阅读全文

摘要： Given an absolute path for a file (Unix-style), simplify it.For example,path="/home/", =>"/home"path="/a/./b/../../c/", =>"/c"click to show corner cas... 阅读全文