2784. Check if Array is Good

You are given an integer array nums. We consider an array good if it is a permutation of an array base[n]. base[n] = [1, 2, ..., n - 1, n, n] (in other words, it is an array of length n + 1 which contains 1 to n - 1 exactly once, plus two occurrences of n). For example, base[1] = [1, 1] and base[3] = [1, 2, 3, 3]. Return true if the given array is good, otherwise return false. Note: A permutati