<p>Given a collection of candidate numbers (<code>candidates</code>) and a target number (<code>target</code>), find all unique combinations in <code>candidates</code>&nbsp;where the candidate numbers sum to <code>target</code>.</p>

<p>Each number in <code>candidates</code>&nbsp;may only be used <strong>once</strong> in the combination.</p>

<p><strong>Note:</strong>&nbsp;The solution set must not contain duplicate combinations.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> candidates = [10,1,2,7,6,1,5], target = 8
<strong>Output:</strong> 
[
[1,1,6],
[1,2,5],
[1,7],
[2,6]
]
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> candidates = [2,5,2,1,2], target = 5
<strong>Output:</strong> 
[
[1,2,2],
[5]
]
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;=&nbsp;candidates.length &lt;= 100</code></li>
	<li><code>1 &lt;=&nbsp;candidates[i] &lt;= 50</code></li>
	<li><code>1 &lt;= target &lt;= 30</code></li>
</ul>

class Solution {
public:
vector< vector<int> > ans;

void func(vector<int>& x, int n,int target,vector<int> v)
{
    if(target==0) 
    {
        ans.push_back(v);
        return;
    }
    if(target<0||n<=0)
    return;
    v.push_back(x[n-1]);
    func(x,n-1,target-x[n-1],v);
    v.pop_back ();
    
    while(n>1&&x[n-1]==x[n-2]) n--;
    func(x,n-1,target,v);
    
}
    vector<vector<int>> combinationSum2(vector<int>& candidates, int target) {
        int n = candidates.size();
        sort(candidates.begin(),candidates.end());
        vector<int> v;
        func(candidates,n,target,v);
        return ans;
    }
};
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