Check if Array is Good — LeetCode 2784 Python Solution

The problem

You are given an integer array nums. We consider an array good if it is a permutation of an array base[n].

Example

Input

nums = [2, 1, 3]

Output

false

Explanation

Since the maximum element of the array is 3, the only candidate n for which this array could be a permutation of base[n], is n = 3. However, base[3] has four elements but array nums has three. Therefore, it can not be a permutation of base[3] = [1, 2, 3, 3]. So the answer is false.

Python solution

class Solution:
    def isGood(self, nums: List[int]) -> bool:
        cnt = Counter(nums)
        n = len(nums) - 1
        return cnt[n] == 2 and all(cnt[i] for i in range(1, n))

Complexity

Pattern: Sorting

Spend O(n log n) once to buy an ordering that makes the rest of the problem trivial. LeetCode 2784. Check if Array is Good is filed here because LeetCode tags it Sorting, which is the vocabulary this hub collects.

The sorting guide has the Python template for the pattern and the 401 LeetCode problems that use it.

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