Maximum Number of Pairs in Array

You're given a 0-indexed integer array, nums. In each operation, you can:

1. Choose two integers in nums that are equal.
2. Remove both integers from nums, forming a pair.

Perform this operation as many times as possible.

Your task is to print a 0-indexed space separated integer array, answer, of size 2, where:

1. answer[0] represents the number of pairs formed.
2. answer[1] represents the number of leftover integers in nums after performing the operation as many times as possible.