<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:
    void func(int i,long sum,int target,unordered_map<int,int>&mp, vector<int>& candidates,vector<vector<int>>& ans,vector<int> temp){
        int n=candidates.size();
        if(i==n){
            if(sum==target){
                ans.push_back(temp);
            }
            return;
        }
        if(sum>target){
            return;
        }
        int k;
        for(k=0;k<=mp[candidates[i]];k++){
            if(sum<=target){
                func(i+1,sum,target,mp,candidates,ans,temp);
                temp.push_back(candidates[i]);
            }else{
                break;
            }
            sum+=candidates[i];
        }
    }
    vector<vector<int>> combinationSum2(vector<int>& candidates, int target) {
        sort(candidates.begin(),candidates.end());
        int n=candidates.size();
        unordered_map<int,int> mp;
        for(int i=0;i<n;i++){
            mp[candidates[i]]++;
        }
        candidates.clear();
        for(auto it=mp.begin();it!=mp.end();it++){
            candidates.push_back(it->first);
        }
        n=candidates.size();
        vector<vector<int>> ans;
        vector<int> temp;
        reverse(candidates.begin(),candidates.end());
        func(0,0,target,mp,candidates,ans,temp);
        return ans;
    }
};
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