Day 25 LeetCode 3375 Minimum Operations to Make Array Values Equal to K.cpp

/*
3375. Minimum Operations to Make Array Values Equal to K
Solved
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.
*/

class Solution {
public:
    int minOperations(vector<int>& nums, int k) {
        unordered_map<int,int> mp;
        for(int i : nums){
            mp[i]++;
            if(i<k)return -1;
        }
        int ans=mp.size();
        if(mp[k]) return ans-1;
        return ans;
    }
};