Minimum Increment to Make Array Unique

lcpy gen -n 945   # by problem number
lcpy gen -s minimum_increment_to_make_array_unique   # by problem name

Input: nums = [1,2,2]
Output: 1
Explanation: After 1 move, the array could be [1, 2, 3].

Input: nums = [3,2,1,2,1,7]
Output: 6
Explanation: After 6 moves, the array could be [3, 4, 1, 2, 5, 7].
It can be shown that it is impossible for the array to have all unique values with 5 or less moves.

class Solution:
    # Time: O(n log n)
    # Space: O(n) for the sorted copy
    def min_increment_for_unique(self, nums: list[int]) -> int:
        moves = 0
        previous = -1
        for num in sorted(nums):
            if num <= previous:
                # Raise num to one above the last placed value
                moves += previous - num + 1
                previous += 1
            else:
                previous = num
        return moves