Height Checker

Posted on | In |
  • Source : Link
  • Author : Han
  • Date : 2022-01-05

Problems

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

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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

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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

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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.

Solution

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class Solution {
    fun heightChecker(heights: IntArray): Int {
        val expect: IntArray = heights.copyOf().also {
            it.sort()
        }
        var count = 0
        heights.forEachIndexed { i, _ ->
            if (heights[i] != expect[i]) {
                count++
            }
        }
        return count
    }
}

It’s better solution

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class Solution {
    fun heightChecker(heights: IntArray): Int {
        return heights.zip(heights.sorted()).count { it.first != it.second }
    }
}