leetcode

Generate Parentheses

Generate Parentheses

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class Solution(object):
    def generateParenthesis(self, n, open=0):
        """
        :type n: int
        :rtype: List[str]
        """
        if n == 0: return [')'*open]
        if open == 0:
            return ['(' + x for x in self.generateParenthesis(n - 1, 1)]
        else:
            return [')' + x for x in self.generateParenthesis(n, open - 1)] + ['(' + x for x in self.generateParenthesis(n - 1, open + 1)]
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example for n = 2
else left branch:
( -> () -> ()( -> ()()
else right branch:
( -> (( -> (())

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