# 1051. Height Checker

<https://leetcode.com/problems/height-checker>

## Description

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`

## ac

```java
```