945. Minimum Increment to Make Array Unique

class Solution:
    def minIncrementForUnique(self, nums: List[int]) -> int:
        nums.sort()
        ans = 0

        for i in range(len(nums) - 1):
            if nums[i] >= nums[i + 1]:
                ans += 1 + (nums[i] - nums[i + 1])
                nums[i + 1] = nums[i] + 1

        return ans

Using counting sort

class Solution:
    def minIncrementForUnique(self, nums: List[int]) -> int:
        maxVal = 0
        minVal = float('inf')
        c = defaultdict(int)
        ans = 0

        for e in nums:
            minVal = min(minVal, e)
            maxVal = max(maxVal, e)
            c[e] += 1


        i = minVal
        while i <= maxVal:
            if c[i] > 1:
                x = c[i] - 1
                ans += x
                c[i + 1] += x
                maxVal = max(maxVal, i + 1)
            i += 1

        return ans