<p>In a warehouse, there is a row of barcodes, where the <code>i<sup>th</sup></code> barcode is <code>barcodes[i]</code>.</p>

<p>Rearrange the barcodes so that no two adjacent barcodes are equal. You may return any answer, and it is guaranteed an answer exists.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<pre><strong>Input:</strong> barcodes = [1,1,1,2,2,2]
<strong>Output:</strong> [2,1,2,1,2,1]
</pre><p><strong class="example">Example 2:</strong></p>
<pre><strong>Input:</strong> barcodes = [1,1,1,1,2,2,3,3]
<strong>Output:</strong> [1,3,1,3,1,2,1,2]
</pre>
<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= barcodes.length &lt;= 10000</code></li>
	<li><code>1 &lt;= barcodes[i] &lt;= 10000</code></li>
</ul>

class Solution {
public:
    vector<int> rearrangeBarcodes(vector<int>& barcodes) {
        unordered_map <int, int> data;
        set<pair<int,int>> s;
        int pos = 0;
        for(auto n: barcodes) data[n]++;
        for(auto it = data.begin(); it != data.end(); it++)
            s.insert({it->second, it->first});
        for(auto it = s.rbegin(); it != s.rend(); it++){
            for(auto cnt = 0; cnt < it->first; cnt++, pos+=2){
                if(pos >= barcodes.size())
                    pos = 1;
                barcodes[pos] = it->second;
            }
        }
        return barcodes;
    }   
};
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