2014年11月9日
Evaluate Reverse Polish Notation(逆波兰式)
摘要： Evaluate the value of an arithmetic expression inReverse Polish Notation.Valid operators are+,-,*,/. Each operand may be an integer or another express... 阅读全文
posted @ 2014-11-09 20:15 雄哼哼 阅读(207) 评论(0) 推荐(0)
Reverse Words in a String
摘要： Given an input string, reverse the string word by word.For example,Given s = "the sky is blue",return "blue is sky the".思路:就是对首尾空格和中间连续空格的处理。为了方便处理，在s... 阅读全文
posted @ 2014-11-09 18:41 雄哼哼 阅读(148) 评论(0) 推荐(0)
Validate Binary Search Tree(DFS)
摘要： Given a binary tree, determine if it is a valid binary search tree (BST).Assume a BST is defined as follows:The left subtree of a node contains only n... 阅读全文
posted @ 2014-11-09 16:12 雄哼哼 阅读(233) 评论(0) 推荐(0)