Is Most Frequent Even Element easy or hard?

Most Frequent Even Element is classified as an Easy problem on LeetCode. It mainly tests basic array traversal, conditional filtering for even numbers, and frequency counting with a hash map.

Most Frequent Even Element Python/Java solution

In Python, use a dictionary or collections.Counter to track counts of even numbers while scanning the array. In Java, use a HashMap to store frequencies and update the answer based on maximum count and smallest value tie-breaking.

How to solve Most Frequent Even Element in O(n)?

Filter even numbers during a single pass and store their counts in a hash map. After updating the frequency for each number, track the maximum count and choose the smallest value when frequencies tie. Hash table insert and lookup operations keep the overall complexity at O(n).

What is the best approach for Most Frequent Even Element?

The best approach is HashMap frequency counting. Iterate through the array, track counts of only even numbers in a hash table, and keep the number with the highest frequency. This method runs in O(n) time with O(k) space where k is the number of distinct even values.

Is Most Frequent Even Element asked at Google/Amazon/Meta?

This problem reflects a common interview pattern involving frequency counting and hash maps. Variations of the problem appear in coding interviews at companies like Amazon and Google where candidates must identify the most frequent element under certain constraints.

What data structure is used in Most Frequent Even Element?

A hash table (HashMap or dictionary) is the primary data structure used in the optimal solution. It stores each even number as a key and its occurrence count as the value, enabling constant-time updates and lookups during traversal.

What is the time complexity of Most Frequent Even Element?

The optimal solution runs in O(n) time because the array is scanned once while updating frequencies in a hash map. An alternative sorting-based solution takes O(n log n) time due to the sorting step before counting consecutive elements.

Description Hints 2 Solution Video 5:43

2404. Most Frequent Even Element

Easy54.0% acceptance2 companies

Given an integer array nums, return the most frequent even element.

If there is a tie, return the smallest one. If there is no such element, return -1.

Example 1:

Input: nums = [0,1,2,2,4,4,1]
Output: 2
Explanation:
The even elements are 0, 2, and 4. Of these, 2 and 4 appear the most.
We return the smallest one, which is 2.

Example 2:

Input: nums = [4,4,4,9,2,4]
Output: 4
Explanation: 4 is the even element appears the most.

Example 3:

Input: nums = [29,47,21,41,13,37,25,7]
Output: -1
Explanation: There is no even element.

Constraints:

1 <= nums.length <= 2000
0 <= nums[i] <= 10⁵

Asked at 2 companies

Google Bloomberg

Topics

Hints open one at a time

Hint 1

Could you count the frequency of each even element in the array?

Hint 2

Would a hashmap help?

5:43

Still stuck?Read 3 approaches, or watch a walkthrough.

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