摘要: Evaluate the value of an arithmetic expression in Reverse Polish Notation. Valid operators are +, -, *, /. Each operand may be an integer or another e 阅读全文
posted @ 2018-02-25 16:33 乐乐章 阅读(145) 评论(0) 推荐(0) 编辑
摘要: Given a string containing just the characters '(' and ')', find the length of the longest valid (well-formed) parentheses substring. For "(()", the lo 阅读全文
posted @ 2018-02-25 16:21 乐乐章 阅读(187) 评论(0) 推荐(0) 编辑
摘要: Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. The brackets must close in the 阅读全文
posted @ 2018-02-25 15:49 乐乐章 阅读(156) 评论(0) 推荐(0) 编辑