LeetCode in Kotlin

1051. Height Checker

Easy

A school is trying to take an annual photo of all the students. The students are asked to stand in a single file line in non-decreasing order by height. Let this ordering be represented by the integer array expected where expected[i] is the expected height of the ith student in line.

You are given an integer array heights representing the current order that the students are standing in. Each heights[i] is the height of the ith student in line (0-indexed).

Return the number of indices where heights[i] != expected[i].

Example 1:

Input: heights = [1,1,4,2,1,3]

Output: 3

Explanation:

heights: [1,1,4,2,1,3]

expected: [1,1,1,2,3,4]

Indices 2, 4, and 5 do not match.

Example 2:

Input: heights = [5,1,2,3,4]

Output: 5

Explanation:

heights: [5,1,2,3,4]

expected: [1,2,3,4,5]

All indices do not match.

Example 3:

Input: heights = [1,2,3,4,5]

Output: 0

Explanation:

heights: [1,2,3,4,5]

expected: [1,2,3,4,5]

All indices match.

Constraints:

• 1 <= heights.length <= 100
• 1 <= heights[i] <= 100

Solution

class Solution {
    fun heightChecker(heights: IntArray): Int {
        var heightDiff = 0
        val count = IntArray(101)
        val actualLine = IntArray(heights.size)
        for (height in heights) {
            count[height]++
        }
        var heightLength = 0
        for (i in count.indices) {
            if (count[i] > 0) {
                for (j in 0 until count[i]) {
                    actualLine[heightLength] = i
                    heightLength++
                }
                count[i] = 0
            }
        }
        for (i in heights.indices) {
            if (actualLine[i] != heights[i]) {
                heightDiff++
            }
        }
        return heightDiff
    }
}

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