945. Minimum Increment to Make Array Unique

Problem

You are given an integer array nums. In one move, you can pick an index i where 0 <= i < nums.length and increment nums[i] by 1.

Return **the minimum number of moves to make every value in *nums* unique**.

The test cases are generated so that the answer fits in a 32-bit integer.

  Example 1:

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

Example 2:

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 with 5 or less moves that it is impossible for the array to have all unique values.

  Constraints:

• 1 <= nums.length <= 10^5

• 0 <= nums[i] <= 10^5

Solution (Java)

class Solution {
    public int minIncrementForUnique(int[] nums) {
        int max = 0;
        for (int num : nums) {
            max = Math.max(max, num);
        }
        int[] counts = new int[nums.length + max];
        for (int num : nums) {
            counts[num]++;
        }
        int minMoves = 0;
        for (int i = 0; i < counts.length; i++) {
            if (counts[i] <= 1) {
                continue;
            }
            int remaining = counts[i] - 1;
            minMoves = minMoves + remaining;
            counts[i + 1] = counts[i + 1] + remaining;
        }
        return minMoves;
    }
}

Explain:

nope.

Complexity:

• Time complexity : O(n).
• Space complexity : O(n).