2206. Divide Array Into Equal Pairs
Easy
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.
Constraints:
nums.length == 2 * n1 <= n <= 5001 <= nums[i] <= 500
from collections import Counter
class Solution:
def divideArray(self, nums: List[int]) -> bool:
# c = Counter(nums)
# for item in c.keys():
# if c[item] % 2 != 0:
# return False
# return True
nset = set()
for n in nums:
if n in nset:
nset.remove(n)
else:
nset.add(n)
return len(nset) == 0