Added minimum platforms required problem

[Siddharthrajrana]

Fixes #9119

Added a new problem based on the Greedy Algorithm: Minimum Platforms Required Problem.

Problem Description

Given arrival and departure times of all trains that reach a railway station. Find the minimum number of platforms required for the railway station so that no train is kept waiting.
Consider that all the trains arrive on the same day and leave on the same day. Arrival and departure time can never be the same for a train but we can have arrival time of one train equal to departure time of the other. At any given instance of time, same platform can not be used for both departure of a train and arrival of another train. In such cases, we need different platforms.

Input: n = 6
arr[] = {0900, 0940, 0950, 1100, 1500, 1800}
dep[] = {0910, 1200, 1120, 1130, 1900, 2000}

Output: 3
Explanation:
Minimum 3 platforms are required to
safely arrive and depart all trains.

Reference: https://practice.geeksforgeeks.org/problems/minimum-platforms-1587115620/1

Solution Approach

First we will sort both arrays. When there is sorted events, it will be easy to maintain
the count of trains that have arrived but not departed. The total platforms needed at one
time can be found by taking the difference between arrivals and departures at that time and
the maximum value of all times will be the final answer.

Checklist:

• I have read CONTRIBUTING.md.
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[rohan472000]

Use ruff . --fix to rectify ruff issues.

[algorithms-keeper]

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Repository:

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• Formatted string literals (f-strings)
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• pytest

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[algorithms-keeper]

Please provide return type hint for the function: minimum_platforms_required. If the function does not return a value, please provide the type hint as: def function() -> None:

Please provide type hint for the parameter: arrival_times

Please provide type hint for the parameter: departure_times

[rohan472000]

Add return type of this fucntion.

[rohan472000]

Add more edge and unique doctests.

[tianyizheng02]

Thank you for your contribution, but unfortunately we're not accepting new PRs at the moment. We're currently trying to clear our backlog of existing PRs in preparation for Hacktoberfest. If you want to contribute, please wait until after October 1 to open a new PR.