Merge pull request #1691 from CodingTestStudy2/최원준

[최원준] Day21

Author: github-actions[bot]

leetcode3/최원준/3866. First Unique Even Element.py

@@ -0,0 +1,7 @@
+class Solution:
+    def firstUniqueEven(self, nums: list[int]) -> int:
+        c = Counter(nums)
+        for num, freq in c.items():
+            if num%2==0 and freq == 1:
+                return num
+        return -1