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A query builder composes groupings from round brackets. A grouping is balanced when every opening bracket is closed in the correct order.
Return how many distinct balanced groupings use exactly n pairs of brackets.
n = 3((()))1(()())2(())()3()(())4()()()55Sign in to keep a note here. It is free, and nobody else can see it.
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O(Catalan(n)) time · O(n) space
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