#2206
Divide Array Into Equal Pairs
easy · verified · 79.2% accepted · 1,194 likes · top 90%
array · hash table · bit manipulation · counting
Description
You are given an integer array nums consisting of 2 * n integers.
You need to divide nums into n pairs such that:
- Each element belongs to exactly one pair.
- The elements present in a pair are equal.
Return true if nums can be divided into n pairs, otherwise return false.
Example 1:
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.
Example 2:
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.
Solution