<p>Given an integer array of even length <code>arr</code>, return <code>true</code><em> if it is possible to reorder </em><code>arr</code><em> such that </em><code>arr[2 * i + 1] = 2 * arr[2 * i]</code><em> for every </em><code>0 &lt;= i &lt; len(arr) / 2</code><em>, or </em><code>false</code><em> otherwise</em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> arr = [3,1,3,6]
<strong>Output:</strong> false
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> arr = [2,1,2,6]
<strong>Output:</strong> false
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> arr = [4,-2,2,-4]
<strong>Output:</strong> true
<strong>Explanation:</strong> We can take two groups, [-2,-4] and [2,4] to form [-2,-4,2,4] or [2,4,-2,-4].
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>2 &lt;= arr.length &lt;= 3 * 10<sup>4</sup></code></li>
	<li><code>arr.length</code> is even.</li>
	<li><code>-10<sup>5</sup> &lt;= arr[i] &lt;= 10<sup>5</sup></code></li>
</ul>

class Solution {
public:
    bool canReorderDoubled(vector<int>& arr) {
        vector<int> pos;
        vector<int> neg;
        int zero=0;

        for (auto i : arr){
            if (i > 0){
                pos.push_back(i);
            } else if (i < 0){
                neg.push_back(i);
            }else{
                zero++;
            }
        }
        sort(pos.begin(), pos.end());
        sort(neg.rbegin(), neg.rend());
         map<int,int> mp;
         map<int,int> mp2;

         for (int i =0; i<pos.size(); i++){
            if (mp.count(pos[i]) == 0){
                mp[pos[i] * 2]++;
            }
            else if (mp[pos[i]] > 1){
                mp[pos[i]]--;
            } else{
                mp.erase(pos[i]);
            }
         }
         for (int i =0; i<neg.size(); i++){
            if (mp2.count(neg[i]) == 0){
                mp2[neg[i] * 2]++;
                cout << neg[i] << " " << mp2[neg[i] * 2] << endl;
            }
            else if (mp2[neg[i]] > 1){
                mp2[neg[i]]--;
            } else{
                mp2.erase(neg[i]);
            }
         }
         cout << mp2.size() << " " << mp.size() << endl;

         if (mp.empty() && mp2.empty() && zero % 2 == 0){
            return true;
         }
         return false;
    }
};
70100