Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. For example, given n = 3, a solution set is: "((()))", "(()())", "(())()", "()(())", "()()()" 在LeetCo
Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. The brackets must close in the correct order, "()" and "()[]{}" are all valid but "(]" and "([)]"
Given a balanced parentheses string S, compute the score of the string based on the following rule: () has score 1 AB has score A + B, where A and B are balanced parentheses strings. (A) has score 2 * A, where A is a balanced parentheses string. Exam
思路: 首先用字典将三对括号存储,遍历字符串中每个字符,遇到左括号就入栈:遇到右括号就开始判断:是否与栈弹出的顶字符相同. 如果到最后栈被清空,说明全部匹配上了,为真. class Solution(object): def isValid(self, s): stack=[] #设置一个列表,把该列表当做栈来使用即可 dic={'(':')','{':'}','[':']'} #使用字典存储括号 new_dic = {v : k for k, v in dic.items()} #由于不能直接
