2404. Most Frequent Even Element

• Time: $O(n)$
• Space: $O(n)$
  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 class Solution { public: int mostFrequentEven(vector& nums) { int ans = -1; unordered_map count; for (const int num : nums) { if (num & 1) continue; const int newCount = ++count[num]; const int maxCount = count[ans]; if (newCount > maxCount || newCount == maxCount && num < ans) ans = num; } return ans; } }; 
  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 class Solution { public int mostFrequentEven(int[] nums) { int ans = -1; Map count = new HashMap<>(); for (final int num : nums) { if (num % 2 == 1) continue; final int newCount = count.merge(num, 1, Integer::sum); final int maxCount = count.getOrDefault(ans, 0); if (newCount > maxCount || newCount == maxCount && num < ans) ans = num; } return ans; } } 
  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 class Solution: def mostFrequentEven(self, nums: List[int]) -> int: ans = -1 count = collections.Counter() for num in nums: if num & 1: continue count[num] += 1 newCount = count[num] maxCount = count[ans] if newCount > maxCount or newCount == maxCount and num < ans: ans = num return ans