solutions: 3375. Minimum Operations to Make Array Values Equal to K (Easy)

Author: wingkwong

solutions/3300-3399/3375-minimum-operations-to-make-array-values-equal-to-k-easy.md

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+---
+description: 'Author: @wkw | https://leetcode.com/problems/minimum-operations-to-make-array-values-equal-to-k/'
+---
+
+# 3375. Minimum Operations to Make Array Values Equal to K (Easy)
+
+## Problem Link
+
+https://leetcode.com/problems/minimum-operations-to-make-array-values-equal-to-k
+
+## Problem Statement
+
+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:**
+
+- $1 <= nums.length <= 100$
+- $1 <= nums[i] <= 100$
+- $1 <= k <= 100$
+
+## Approach 1: Check Distinct Numbers
+
+<Tabs>
+<TabItem value="py" label="Python">
+<SolutionAuthor name="@wkw"/>
+
+```py
+# TC: O(n)
+# SC: O(1)
+class Solution:
+    def minOperations(self, nums: List[int], k: int) -> int:
+        # we can just focus on distinct numbers in $nums$
+
+        # in example 1, d = {5, 4, 2}
+        # we can see that the numbers > 2 are 5 and 4, so the answer is 2
+        # in op1, we can choose h = 4 to make [5,2,5,4,5] to [4,2,4,4,4]
+        # in op2, we can choose h = 2 to make [4,2,4,4,4] to [2,2,2,2,2]
+
+        # in example 2, d = {1, 2}
+        # since 1 < 2 so it is not possible to make all elements equal to k,
+        # hence we return -1 in this case
+
+        # if there is a number $x$ that is less than $k$,
+        # then return -1
+        if any(x < k for x in nums): return -1
+        # otherwise check the size of the unique number that is greater than k
+        return len(set(x for x in nums if x > k))
+```
+
+</TabItem>
+</Tabs>