I Problem

Given an integer array nums and an integer k, return the k most frequent elements. You may return the answer in any order.

Example 1
Input: nums = [1, 1, 1, 2, 2, 3], k = 2
Output: [1, 2]

I Problem

Given two strings ransomNote and magazine, return true if ransomNote can be constructed by using the letters from magazine and false otherwise.

Each letter in magazine can only be used once in ransomNote.