[LeetCode] 3375. Minimum Operations to Make Array Values Equal to K (Python)

 

 

난이도: Easy

Problem Description

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You are given an integer array nums and an integer k.

 

An integer h is called valid if all values in the array that are strictly greater than h are identical.

 

For example, if nums = [10, 8, 10, 8], a valid integer is h = 9 because all nums[i] > 9 are equal to 10, but 5 is not a valid integer.

 

You are allowed to perform the following operation on nums:

• Select an integer h that is valid for the current values in nums.
• For each index i where nums[i] > h, set nums[i] to h.

Return the minimum number of operations required to make every element in nums equal to k. If it is impossible to make all elements equal to k, return -1.

 

Problem Example

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Example 1:

Input: nums = [5,2,5,4,5], k = 2

Output: 2

Explanation:

The operations can be performed in order using valid integers 4 and then 2.

Example 2:

Input: nums = [2,1,2], k = 2

Output: -1

Explanation:

It is impossible to make all the values equal to 2.

Example 3:

Input: nums = [9,7,5,3], k = 1

Output: 4

Explanation:

The operations can be performed using valid integers in the order 7, 5, 3, and 1.

 

Constraints

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• 1 <= nums.length <= 100
• 1 <= nums[i] <= 100
• 1 <= k <= 100

 

 

✏️ Solution

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class Solution:
    def minOperations(self, nums: List[int], k: int) -> int:
        if min(nums) < k:
            return -1
        
        nums = set(nums)

        return len(nums) if k not in nums else len(nums)-1

문제를 읽었을 때 복잡해 보일 수 있지만, 좀만 생각해보면 쉽게 풀 수 있는 문제였다.

 

일단 nums의 최소값이 k보다 작으면 -1을 return한다.

 

그리고 nums의 요소를 중복을 없애기 위해 set으로 변환시켜주었다.

 

이 때, set 안에 k 값이 들어있으면 걔는 변환을 안시켜도 되기 때문에 len(nums)-1을 return하였고, k 값이 안들어 있다면 모두 변환해주어야 하기 때문에 len(nums)를 return 하여 정답을 맞을 수 있었다.

 

 

⚙️ Runtime & Memory

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문제: 3375. Minimum Operations to Make Array Values Equal to K

 

깃허브: github

algorithmPractice/LeetCode/3621-minimum-operations-to-make-array-values-equal-to-k at main · laewonJeong/algorithmPractice