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题目链接Givennpairs of parentheses, write a function to generate all combinations of well-formed parentheses.For example, givenn= 3, a solution set is:"((... 阅读全文
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题目链接Given a string containing just the characters'(',')','{','}','['and']', determine if the input string is valid.The brackets must close in the corr... 阅读全文
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题目链接The count-and-say sequence is the sequence of integers beginning as follows:1, 11, 21, 1211, 111221, ...1is read off as"one 1"or11.11is read off a... 阅读全文