1674. Minimum Moves to Make Array Complementary

https://leetcode.com/problems/minimum-moves-to-make-array-complementary

Description

You are given an integer array nums of even length n and an integer limit. In one move, you can replace any integer from nums with another integer between 1 and limit, inclusive.

The array nums is complementary if for all indices i (0-indexed), nums[i] + nums[n - 1 - i] equals the same number. For example, the array [1,2,3,4] is complementary because for all indices i, nums[i] + nums[n - 1 - i] = 5.

Return the minimum number of moves required to make nums complementary.

Example 1:

**Input:** nums = [1,2,4,3], limit = 4
**Output:** 1
**Explanation:** In 1 move, you can change nums to [1,2,2,3] (underlined elements are changed).
nums[0] + nums[3] = 1 + 3 = 4.
nums[1] + nums[2] = 2 + 2 = 4.
nums[2] + nums[1] = 2 + 2 = 4.
nums[3] + nums[0] = 3 + 1 = 4.
Therefore, nums[i] + nums[n-1-i] = 4 for every i, so nums is complementary.

Example 2:

**Input:** nums = [1,2,2,1], limit = 2
**Output:** 2
**Explanation:** In 2 moves, you can change nums to [2,2,2,2]. You cannot change any number to 3 since 3 > limit.

Example 3:

**Input:** nums = [1,2,1,2], limit = 2
**Output:** 0
**Explanation:** nums is already complementary.

Constraints:

• n == nums.length

• 2 <= n <= 105

• 1 <= nums[i] <= limit <= 105

• n is even.

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