<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 {
public:
    vector<string> ans;
    map<string, bool> m;
    vector<string> generateParenthesis(int n) {
        findAns(n, 0, "");
        return ans;
    }

    void findAns(int n, int coda, string s)
    {
        if (coda < 0)
            return;
        if (s.size() == n*2)
        {
            if (coda == 0)
                ans.push_back(s);
            return;
        }
        string tmp = s;
        findAns(n, coda+1, s+'(');
        findAns(n, coda-1, s+')');
    }
};
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