## DEV Community

Abhishek Chaudhary

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# Height Checker

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:
def heightChecker(self, heights: List[int]) -> int:
n = len(heights)
expected = sorted(heights)
return len([i for i in range(n) if heights[i] != expected[i]])
``````

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Timeless DEV post...

## Git Concepts I Wish I Knew Years Ago

The most used technology by developers is not Javascript.

It's not Python or HTML.

It hardly even gets mentioned in interviews or listed as a pre-requisite for jobs.

I'm talking about Git and version control of course.