<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>> out;
    vector<vector<int>> fin;

    vector<vector<int>> combinationSum2(vector<int>& candidates, int target) {
        sort(candidates.begin(), candidates.end(), greater<int>());
        
        // if(checkPossible(candidates, target)) {
            gen(0, 0, {}, candidates, target);
        // }

        // vector<vector<int>> fin(out.begin(), out.end());

        return fin;
    }

    // bool checkPossible(vector<int>& candidates, int& target) {
    //     int temp = 0;

    //     for(int x = 0; x < candidates.size() && temp < target; x++) {
    //         temp += candidates[x];
    //     }

    //     return temp >= target;
    // }

    void gen(int sum, int index, vector<int> curr, vector<int>& nums, int &target) {
        if(sum == target) {
            // sort(curr.begin(), curr.end());
            // out.insert(curr);
            fin.push_back(curr);
            return;
        }

        if(index >= nums.size() || sum > target) {
            // cout << "Exited" << endl;
            return;
        }

        // Add
        curr.push_back(nums[index]);
        gen(sum + curr.back(), index + 1, curr, nums, target);
        
        curr.pop_back();

        // Skip all matching elements
        while(index < nums.size() - 1 && nums[index] == nums[index + 1]) {
            index++;
        }

        gen(sum, index + 1, curr, nums, target);
    }
};
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