<p>Given <code>n</code> pairs of parentheses, write a function to <em>generate all combinations of well-formed parentheses</em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<pre><strong>Input:</strong> n = 3
<strong>Output:</strong> ["((()))","(()())","(())()","()(())","()()()"]
</pre><p><strong class="example">Example 2:</strong></p>
<pre><strong>Input:</strong> n = 1
<strong>Output:</strong> ["()"]
</pre>
<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= n &lt;= 8</code></li>
</ul>

class Solution:
    def generateParenthesis(self, n: int) -> List[str]:
        answer = []

        def backtrack(current, left, right):
            if len(current) == 2*n:
                answer.append(current)

            if left<n:
                backtrack(current+'(', left+1, right)
            if right<left:
                backtrack(current+')', left, right+1)

        backtrack('',0,0)
        return answer
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