<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:set<vector<int>>dp;
void help(int idx,int tar,int n,vector<int>& candi,vector<int>& t)
{
    if(tar==0)
    {
        dp.insert(t);
        return;
    }
    if(idx==n)
     return;
     for(int i=idx;i<n;i++)
     {
        if(tar<candi[i] )
        return;
        if(i>idx && candi[i]==candi[i-1])
        continue;
        t.push_back(candi[i]);
       
        help(i+1,tar-candi[i],n,candi,t);
        t.pop_back();
     }
}
    vector<vector<int>> combinationSum2(vector<int>& candi, int target) {
        sort(candi.begin(),candi.end());
        int n=candi.size();
        vector<int>t;
         help(0,target,n,candi,t);
         return vector<vector<int>>(dp.begin(),dp.end());
    }
};
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