Is Minimum Number of Operations to Make Arrays Similar easy or hard?

The problem is rated Hard because the key constraint is not immediately obvious. Recognizing that operations preserve parity is the main insight. Once that observation is made, the solution reduces to greedy matching with sorting.

Minimum Number of Operations to Make Arrays Similar Python/Java solution

Most implementations follow the same pattern: split nums and target into odd and even lists, sort each list, then sum positive differences between corresponding elements. This logic translates directly to Python, Java, C++, and JavaScript with identical O(n log n) complexity.

How to solve Minimum Number of Operations to Make Arrays Similar in O(n)?

A near O(n) solution can be achieved using counting or frequency maps when value ranges are manageable. Elements are grouped by parity, then differences between required and current frequencies are aggregated. The total adjustment divided by 2 gives the operation count.

What is the best approach for Minimum Number of Operations to Make Arrays Similar?

The most effective approach is greedy matching with sorting. Separate both arrays into odd and even groups because operations of +/-2 never change parity. Sort each parity group and compare corresponding elements to compute the required adjustments. This approach runs in O(n log n) time and O(n) space.

Is Minimum Number of Operations to Make Arrays Similar asked at Google/Amazon/Meta?

Greedy and parity-based transformation problems similar to this appear in interviews at companies like Google, Amazon, and Meta. They test recognition of invariants, greedy matching, and efficient use of sorting or frequency counting.

What data structure is used in Minimum Number of Operations to Make Arrays Similar?

The solution primarily uses arrays or lists to separate odd and even numbers. Sorting algorithms and sometimes hash maps or frequency counters are used to match elements and compute required differences efficiently.

What is the time complexity of Minimum Number of Operations to Make Arrays Similar?

The optimal solution runs in O(n log n) time due to sorting the parity-separated arrays. After sorting, a single pass computes the difference between elements to determine the number of operations. Space complexity is O(n) for storing the separated groups.

2449. Minimum Number of Operations to Make Arrays Similar - Practice Online

You are given two positive integer arrays nums and target, of the same length.

In one operation, you can choose any two distinct indices i and j where 0 <= i, j < nums.length and:

set nums[i] = nums[i] + 2 and
set nums[j] = nums[j] - 2.

Two arrays are considered to be similar if the frequency of each element is the same.

Return the minimum number of operations required to make nums similar to target. The test cases are generated such that nums can always be similar to target.

Example 1:

Input: nums = [8,12,6], target = [2,14,10]
Output: 2
Explanation: It is possible to make nums similar to target in two operations:
- Choose i = 0 and j = 2, nums = [10,12,4].
- Choose i = 1 and j = 2, nums = [10,14,2].
It can be shown that 2 is the minimum number of operations needed.

Example 2:

Input: nums = [1,2,5], target = [4,1,3]
Output: 1
Explanation: We can make nums similar to target in one operation:
- Choose i = 1 and j = 2, nums = [1,4,3].

Example 3:

Input: nums = [1,1,1,1,1], target = [1,1,1,1,1]
Output: 0
Explanation: The array nums is already similiar to target.

Constraints:

n == nums.length == target.length
1 <= n <= 10⁵
1 <= nums[i], target[i] <= 10⁶
It is possible to make nums similar to target.