LeetCode in Kotlin

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:

Solution

class Solution {
    fun minIncrementForUnique(nums: IntArray): Int {
        var max = 0
        for (num in nums) {
            max = Math.max(max, num)
        }
        val counts = IntArray(nums.size + max)
        for (num in nums) {
            counts[num]++
        }
        var minMoves = 0
        for (i in counts.indices) {
            if (counts[i] <= 1) {
                continue
            }
            val remaining = counts[i] - 1
            minMoves += remaining
            counts[i + 1] = counts[i + 1] + remaining
        }
        return minMoves
    }
}