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.