<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>* sol;
    void solve(string stack, int tar, int ocnt, int ccnt)
    {
        if (ocnt == tar && ccnt == tar) {
            sol->push_back(stack);
            return;
        }
        if (ocnt < tar) {
            solve(stack + '(', tar, ocnt + 1, ccnt);
        }
        if (ccnt < tar && ccnt < ocnt) {
            solve(stack + ')', tar, ocnt, ccnt + 1);
        }
    }
    vector<string> generateParenthesis(int n) {
        string tmp = "";
        sol = new vector<string>();
        solve(tmp, n, 0, 0);

        return (*sol);
    }
};
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