<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:
    // bool isSafe(vector<vector<int>>&result,vector<int>&combination){
    //     for(int i=0; i<result.size(); i++){
    //         if(result[i]==combination){
    //             return false;
    //         }
    //     }
    //     return true;
    // }
    void solve(vector<int>&candidates, int target, int start, 
    vector<int>combination, vector<vector<int>>&result){
      
            if(target == 0 ){
            result.push_back(combination);
            return;
        }
      

        if(target < 0){
            return;
        }

        for(int i=start; i<candidates.size(); i++){
            if(i > start && candidates[i]==candidates[i-1]){
                continue;
            }
            combination.push_back(candidates[i]);
            solve(candidates, target-candidates[i], i+1, combination,result);
            combination.pop_back();
        }
    }
    vector<vector<int>> combinationSum2(vector<int>& candidates, int target) {
        vector<vector<int>>result;
        vector<int>combination;
        int start=0;
        sort(candidates.begin(),candidates.end());
        solve(candidates,target,start,combination,result);
        // set<vector<int>>st;
        // for(auto e:result){
        //     st.insert(e);
        // }
        // result.clear();
        // for(auto e:st){
        //     result.push_back(e);
        // }
        return result;
        
    }
};
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