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https://github.com/emilwijayasekara/leetcode-1051-height-checker

LeetCode Problem 1051. Height Checker - determining the number of students in a school lineup whose heights do not match the expected non-decreasing order for an annual photo. The task is to compare the given array of student heights with the array representing the expected order and count the indices where disparities occur.
https://github.com/emilwijayasekara/leetcode-1051-height-checker

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LeetCode Problem 1051. Height Checker - determining the number of students in a school lineup whose heights do not match the expected non-decreasing order for an annual photo. The task is to compare the given array of student heights with the array representing the expected order and count the indices where disparities occur.

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# LeetCode Practice  (Day 11)



## Achievements



[![Leetcode-copy.jpg](https://i.postimg.cc/cLgp9v0n/Leetcode-copy.jpg)](https://postimg.cc/Js8Yt4yr)



## About the problem

- *Problem Number* : 1051

- *Problem Name* :  [Height Checker](https://leetcode.com/problems/height-checker/description/ "https://leetcode.com/problems/height-checker/description/")

- *Problem difficulty* : Easy (76.21%)🟢

- *Programming language used* - Java



## Problem



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`



## Approach Explanation



I began by creating a duplicate array, `sortedArray`, using `Arrays.copyOf` to replicate the original student heights. The purpose of this duplicated array was to represent the expected order of heights, and I achieved this by sorting it using `Arrays.sort`.



The comparison process was then simplified by iterating through both the original `heights` array and the sorted array simultaneously. At each index, I checked whether the height in the original array matched the corresponding height in the sorted array. If a mismatch was detected, I incremented the `count` variable to keep track of the number of indices where the heights did not align with the expected order.



### If you have suggestions for improvement or would like to contribute to this solution, feel free to create a pull request. 🙌😇