<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>& arr, int target) {
        
        map<int,int> mp;

        for( int v: arr) {
            mp[v] += 1;
        }

        vector< vector< vector<int> > > dp( target+1, vector< vector<int> >());

        dp[0].push_back(vector<int>());

        for( auto p: mp) {
            for( int v=target; v>=0; v--) {
                for( vector<int> arr: dp[v]) {
                    for( int j=1; (j<=p.second) && (v+j*p.first<=target); j++) {
                        arr.push_back(p.first);
                        dp[v+j*p.first].push_back(arr);
                    }
                }
            }
        }
        
        return dp[target];
    }
};
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