Count Frequencies

Given an array of integers, count how many times each number appears. Return a hash map where keys are the numbers from the array and values are their frequencies.

Input

arr: an array of integers

Output

A hash map mapping each number to its frequency (count of occurrences)

Examples

Example 1:

Input: arr = [1, 2, 2, 3, 3, 3]

Output: {1: 1, 2: 2, 3: 3}

Explanation: 1 appears once, 2 appears twice, 3 appears three times.

Example 2:

Input: arr = [5, 5, 5, 5]

Output: {5: 4}

Explanation: 5 appears four times.

Example 3:

Input: arr = [1, 2, 3, 4]

Output: {1: 1, 2: 1, 3: 1, 4: 1}

Explanation: Each number appears exactly once.