<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:
    vector<vector<int>> combinationSum2(vector<int>& candidates, int target) {
        vector<vector<int>> res;
        map<int, set<vector<int>>> imap, tempmap;
        
        sort(candidates.begin(), candidates.end());
        
        for (auto& val : candidates) {
            for (auto& [sum, iivec] : imap) {
                if (sum + val == target) {
                    for (auto ivec : iivec) {
                        ivec.push_back(val);
                        tempmap[sum+val].insert(ivec);
                    }
                } else if (sum + val < target) {
                    for (auto ivec : iivec) {
                        ivec.push_back(val);
                        tempmap[sum+val].insert(ivec);
                    }
                }
            }
            for (auto& [sum, iivec] : tempmap)
                for (auto& ivec : iivec)
                    imap[sum].insert(ivec);
            tempmap.clear();
            imap[val].insert({val});
        }
        res = vector<vector<int>>(imap[target].begin(), imap[target].end());
        auto it = unique(res.begin(), res.end());
        res.erase(it, res.end());
        return res;
    }
};
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