LeetCode-in-Java

3375. Minimum Operations to Make Array Values Equal to K

Easy

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.

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:

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

Solution

import java.util.HashSet;
import java.util.Set;

public class Solution {
    public int minOperations(int[] nums, int k) {
        Set<Integer> s = new HashSet<>();
        for (int i : nums) {
            s.add(i);
        }
        int res = 0;
        for (int i : s) {
            if (i > k) {
                res++;
            } else if (i < k) {
                return -1;
            }
        }
        return res;
    }
}

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