22. Generate Parentheses

Medium

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Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses.

Example 1:

Input: n = 3
Output: ["((()))","(()())","(())()","()(())","()()()"]

Example 2:

Input: n = 1
Output: ["()"]

Constraints:

• 1 <= n <= 8

class Solution:
    def generateParenthesis(self, n: int) -> List[str]:
        result = []
        def recursion(start, end, path):
            if start == 0 and end == 0:
                result.append(path[:])
            if start > 0:
                recursion(start-1, end, path + '(')
            if end > 0 and end > start:
                recursion(start, end-1, path + ')')
        recursion(n,n,'')
        return result