divide-array-into-equal-pairs

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Algorithms

You are given an integer array <code>nums</code> consisting of <code>2 * n</code> integers.

You need to divide <code>nums</code> into <code>n</code> pairs such that:

<ul>
	<li>Each element belongs to exactly one pair.</li>
	<li>The elements present in a pair are equal.</li>
</ul>

Return <code>true</code> if nums can be divided into <code>n</code> pairs, otherwise return <code>false</code>.

&nbsp;
Example 1:

<pre>
Input: nums = [3,2,3,2,2,2]
Output: true
Explanation: 
There are 6 elements in nums, so they should be divided into 6 / 2 = 3 pairs.
If nums is divided into the pairs (2, 2), (3, 3), and (2, 2), it will satisfy all the conditions.
</pre>

Example 2:

<pre>
Input: nums = [1,2,3,4]
Output: false
Explanation: 
There is no way to divide nums into 4 / 2 = 2 pairs such that the pairs satisfy every condition.
</pre>

&nbsp;
Constraints:

<ul>
	<li><code>nums.length == 2 * n</code></li>
	<li><code>1 &lt;= n &lt;= 500</code></li>
	<li><code>1 &lt;= nums[i] &lt;= 500</code></li>
</ul>