<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:
    ///////////////////////   Consumes extra space ////////////////
    // void combination(int ind,vector<int> &temp,set<vector<int>> &ans,int target,vector<int> candidates){
    //     if(ind>=candidates.size()){
    //         if(target==0){
    //             ans.insert(temp);
    //         }
    //         return;
    //     }
    //     if(candidates[ind]<=target){
    //         temp.push_back(candidates[ind]);
    //         combination(ind+1,temp,ans,target-candidates[ind],candidates);
    //         temp.pop_back();
    //     }
    //     combination(ind+1,temp,ans,target,candidates);
    // }
    void combination(int ind,vector<int> &temp,vector<vector<int>> &ans,int target,vector<int> num){
        
        if(target==0){
            ans.push_back(temp);
            return;
        }
    
        for(int i=ind;i<num.size();i++){
            if(i>ind&&num[i]==num[i-1])continue;
            if(num[i]>target) break;
            temp.push_back(num[i]);
            combination(i+1,temp,ans,target-num[i],num);
            temp.pop_back();
        }
    }
    vector<vector<int>> combinationSum2(vector<int>& candidates, int target) {
        // set<vector<int>> ans;
        vector<vector<int>>ans;
        vector<int> temp;
        int ind=0;
        sort(candidates.begin(),candidates.end());
        combination(ind,temp,ans,target,candidates);
        return ans;  
    }
};
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