DDSA Solutions

3375. Minimum Operations to Make Array Values Equal to K

MediumView on LeetCode
ArrayHash Table
Time: O(n)
Space: O(n)

Problem Overview

Minimum operations to make array values equal to k.

Intuition

Minimum operations to make array values equal to k. All elements must be reducible to k.

Algorithm

  1. 1If any element < k: return -1. Count distinct values > k (each needs one operation).

Common Pitfalls

  • •Can only decrease values. If element < k: impossible. Each distinct value > k needs one op.
3375.cs
C#
// Approach: Collect unique values > k; if any < k return -1; else count distinct unique values > k.
// Time: O(n) Space: O(n)

public class Solution
{
    public int MinOperations(int[] nums, int k)
    {
        HashSet<int> numsSet = new HashSet<int>(nums);
        int mn = nums.Min();
        if (mn < k)
            return -1;
        if (mn > k)
            return numsSet.Count;
        return numsSet.Count - 1;
    }
}
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