<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;
        vector<int> zero;
        for(int i=0;i<arr.size();i++){
            if(arr[i]>0) pos.push_back(arr[i]);
            else if(arr[i]<0) neg.push_back(arr[i]);
            else zero.push_back(arr[i]);
        }
        sort(pos.begin(),pos.end());
        sort(neg.begin(),neg.end(),greater<int>());
        //cout<<helper(pos)<<" "<<helper(neg)<<" "<<helper(zero);
        return helper1(pos) && helper2(neg) && helper1(zero);
    }

    bool helper1(vector<int>& arr) {
        if(arr.size()==0) return true;
        if(arr.size()%2==1) return false;
        //sort(arr.begin(),arr.end());
        priority_queue<int> pq;
        int n=arr.size();
        map<int,int> mp;
        for(int i=0;i<n;i++){
            mp[arr[i]]++;
        }
        for(int i=0;i<n;i++){
            pq.push(arr[i]);
        }
        while(!pq.empty()){
            int ele=pq.top();
            pq.pop();
            if(mp[ele]==0) continue;
            mp[ele]--;
            if(ele%2!=0 || mp[ele/2]==0) return false;
            mp[ele/2]--;
        }
        return true;
    }

    bool helper2(vector<int>& arr) {
        if(arr.size()==0) return true;
        if(arr.size()%2==1) return false;
        //sort(arr.begin(),arr.end());
        priority_queue<int,vector<int>,greater<int>> pq;
        int n=arr.size();
        map<int,int> mp;
        for(int i=0;i<n;i++){
            mp[arr[i]]++;
        }
        for(int i=0;i<n;i++){
            pq.push(arr[i]);
        }
        while(!pq.empty()){
            int ele=pq.top();
            pq.pop();
            if(mp[ele]==0) continue;
            mp[ele]--;
            if(ele%2!=0 || mp[ele/2]==0) return false;
            mp[ele/2]--;
        }
        return true;
    }
};
71500