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 "([)]" are not. 给定一个字符串，只包含字符“（'，”），“{”，“}”，“，”和“，”，确定输入字符串是否有效。括号必须以正确的顺序关闭，“（）”和“（”）{“都是
(String[] args)
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