945. Minimum Increment to Make Array Unique

Medium

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 <= 105
• 0 <= nums[i] <= 105

Solution:

class Solution {

    /**
     * @param Integer[] $nums
     * @return Integer
     */
    function minIncrementForUnique($nums) {
        $ans = 0;
        $minAvailable = 0;

        sort($nums);

        foreach ($nums as $num) {
            $ans += max($minAvailable - $num, 0);
            $minAvailable = max($minAvailable, $num) + 1;
        }

        return $ans;
    }
}

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