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London | 26-Jul-SDC | Alex Jamshidi | Sprint 5 | Implement laptop allocation #685

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c62be7b
added simulation for laptop allocation
Alex-Jamshidi Sep 2, 2026
9d05e3c
removed .venv
Alex-Jamshidi Sep 2, 2026
c385378
updated choices to sample to ensure unique OS preferences
Alex-Jamshidi Sep 2, 2026
306f422
Allocation implemented
Alex-Jamshidi Sep 3, 2026
4c9c603
Add README for Laptop Allocation Program
Alex-Jamshidi Sep 3, 2026
f67da51
Fix spelling and formatting in README.md
Alex-Jamshidi Sep 3, 2026
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1 change: 1 addition & 0 deletions implement-laptop-allocation/.gitignore
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.venv
29 changes: 29 additions & 0 deletions implement-laptop-allocation/README.md
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@LonMcGregor LonMcGregor Oct 7, 2026

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Thanks for writing this readme, it's always good to see programs documented well like this.

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# Laptop Allocation Program

## About
A program that assigns laptops to people based on a list of operating system preferences, it includes a simulation that can be re-run to simulate different scenarios.

## Specification
Create a program that alllocate laptops to people based on a list of preferred operating systems. Every person should be allocated exactly one laptop.

If we define "sadness" as the number of places down in someone's ranking the operating system the ended up with (i.e. if your preferences were [UBUNTU, ARCH, MACOS] and you were allocated a MACOS machine your sadness would be 2), we want to minimise the total sadness of all people. If we allocate someone a laptop with an operating system not in their preferred list, treat them as having a sadness of 100.

## To run code
python3 -m venv .venv
. .venv/bin/activate
pip install -r requirements.txt
python3 simulate.py

## About Allocation
Allocation of laptops works using the Hungarian algorithm.
This is achieved using the linear_sum_assignment function in scipy which acts on a cost matrix constructed from the possible combinations between each person and laptop.

## About Simulation
To test the code for different scenarios, a simulation was created, which simulates:
- A random laptop to person ratio between 0.5 and 2
- A random number of people between 10 and 100
- Therefore a theoretical random number of laptops between 5 and 200
- Random percentage chances a person will be created with 1, 2 or 3 preferred operating systems (randomly assigned)

When the simulation is run the statistics and output data are logged to a log.txt file and partially to the terminal.
An example of a simulation is shown in this repo in log.txt.
53 changes: 53 additions & 0 deletions implement-laptop-allocation/laptop_allocation.py
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# ----- Imports
from dataclasses import dataclass
from enum import Enum

from scipy.optimize import linear_sum_assignment


# ----- Classes
class OperatingSystem(Enum):
MACOS = "macOS"
ARCH = "Arch Linux"
UBUNTU = "Ubuntu"


@dataclass(frozen=True)
class Person:
name: str
age: int
# Sorted in order of preference, most preferred is first.
preferred_operating_systems: tuple[OperatingSystem, ...]

@LonMcGregor LonMcGregor Oct 7, 2026

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Is there a reason you use a tuple here? Is there an advantage of that over another type of structure?



@dataclass(frozen=True)
class Laptop:
id: int
manufacturer: str
model: str
screen_size_in_inches: float
operating_system: OperatingSystem


# ----- Functions
def allocate_laptops(
people: list[Person], laptops: list[Laptop]
) -> dict[Person, Laptop]:
cost_matrix = []
for person in people:
person_costs = []
for laptop in laptops:
if laptop.operating_system in person.preferred_operating_systems:
sadness = person.preferred_operating_systems.index(
laptop.operating_system
)
else:
sadness = 100
person_costs.append(sadness)
cost_matrix.append(person_costs)

row_ind, col_ind = linear_sum_assignment(cost_matrix)

@LonMcGregor LonMcGregor Oct 7, 2026

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Using this algorithm is a good way of optimising laptop assignment. I have a couple of questions:

  1. What do you think the complexity of this approach is?
  2. Does this algorithm have any drawbacks or limitations?
  3. Do you understand how this algorithms works? Can you briefly describe it?


return {
people[p_index]: laptops[l_index] for p_index, l_index in zip(row_ind, col_ind)
}
135 changes: 135 additions & 0 deletions implement-laptop-allocation/log.txt
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-------------------------------------------
Simulation created at: 03-09-2026 04:29:49
-------------------------------------------
Laptop to person weighting = 0.84
Number of People: 21
Number of Laptops: 17

Laptop surplus/deficit: -4

Percentage chance of 1 preference: 48.75%
Percentage chance of 2 preference: 11.71%
Percentage chance of 3 preference: 39.55%

===== List of Laptops =====
ID: 1 | Manufacturer: Dell | Model: XPS | Screen size (inches): 15 | OS: Ubuntu
ID: 2 | Manufacturer: Dell | Model: XPS | Screen size (inches): 13 | OS: Arch Linux
ID: 3 | Manufacturer: Dell | Model: XPS | Screen size (inches): 16 | OS: Arch Linux
ID: 4 | Manufacturer: Dell | Model: XPS | Screen size (inches): 14 | OS: Ubuntu
ID: 5 | Manufacturer: Dell | Model: XPS | Screen size (inches): 13 | OS: Ubuntu
ID: 6 | Manufacturer: Dell | Model: XPS | Screen size (inches): 16 | OS: Arch Linux
ID: 7 | Manufacturer: Dell | Model: XPS | Screen size (inches): 17 | OS: Ubuntu
ID: 8 | Manufacturer: Apple | Model: macBook | Screen size (inches): 16 | OS: macOS
ID: 9 | Manufacturer: Dell | Model: XPS | Screen size (inches): 13 | OS: Ubuntu
ID: 10 | Manufacturer: Dell | Model: XPS | Screen size (inches): 13 | OS: Arch Linux
ID: 11 | Manufacturer: Apple | Model: macBook | Screen size (inches): 17 | OS: macOS
ID: 12 | Manufacturer: Dell | Model: XPS | Screen size (inches): 14 | OS: Ubuntu
ID: 13 | Manufacturer: Dell | Model: XPS | Screen size (inches): 15 | OS: Arch Linux
ID: 14 | Manufacturer: Dell | Model: XPS | Screen size (inches): 15 | OS: Ubuntu
ID: 15 | Manufacturer: Dell | Model: XPS | Screen size (inches): 17 | OS: Arch Linux
ID: 16 | Manufacturer: Apple | Model: macBook | Screen size (inches): 16 | OS: macOS
ID: 17 | Manufacturer: Dell | Model: XPS | Screen size (inches): 16 | OS: Ubuntu

===== List of People =====
Name: Person 1 | Age: 45 | Preferred OS: Ubuntu
Name: Person 2 | Age: 46 | Preferred OS: macOS, Arch Linux, Ubuntu
Name: Person 3 | Age: 56 | Preferred OS: Ubuntu
Name: Person 4 | Age: 85 | Preferred OS: Arch Linux, Ubuntu
Name: Person 5 | Age: 60 | Preferred OS: macOS, Ubuntu, Arch Linux
Name: Person 6 | Age: 89 | Preferred OS: Arch Linux, Ubuntu
Name: Person 7 | Age: 62 | Preferred OS: macOS
Name: Person 8 | Age: 21 | Preferred OS: macOS
Name: Person 9 | Age: 59 | Preferred OS: macOS
Name: Person 10 | Age: 46 | Preferred OS: macOS
Name: Person 11 | Age: 82 | Preferred OS: macOS
Name: Person 12 | Age: 33 | Preferred OS: Arch Linux, macOS, Ubuntu
Name: Person 13 | Age: 33 | Preferred OS: Arch Linux
Name: Person 14 | Age: 48 | Preferred OS: Ubuntu, Arch Linux, macOS
Name: Person 15 | Age: 67 | Preferred OS: Ubuntu, macOS, Arch Linux
Name: Person 16 | Age: 26 | Preferred OS: macOS, Arch Linux, Ubuntu
Name: Person 17 | Age: 66 | Preferred OS: macOS
Name: Person 18 | Age: 31 | Preferred OS: Ubuntu, macOS, Arch Linux
Name: Person 19 | Age: 42 | Preferred OS: Arch Linux, Ubuntu, macOS
Name: Person 20 | Age: 97 | Preferred OS: Arch Linux, Ubuntu, macOS
Name: Person 21 | Age: 79 | Preferred OS: Ubuntu

Laptop operating system options:
Arch Linux: 6
Ubuntu: 8
macOS: 3

First choice of operating systems:
Arch Linux: 6
Ubuntu: 6
macOS: 9

Second choice of operating systems:
Arch Linux: 3
Ubuntu: 5
macOS: 3

Third choice of operating systems:
Arch Linux: 3
Ubuntu: 3
macOS: 3

First choice OS given: 15
Second choice OS given: 1
Third choice OS given: 1

>>>>> Total Sadness Score: 403 <<<<<

Note: Due to a deficit of 4 laptops, the minimum sadness score theoretically achievable could never be less than 400

===== Allocations =====
Person 1 -- Preferred OS: Ubuntu
----> Laptop ID: 1 -- OS: Ubuntu

Person 2 -- Preferred OS: macOS | Arch Linux | Ubuntu
----> Laptop ID: 8 -- OS: macOS

Person 3 -- Preferred OS: Ubuntu
----> Laptop ID: 4 -- OS: Ubuntu

Person 4 -- Preferred OS: Arch Linux | Ubuntu
----> Laptop ID: 2 -- OS: Arch Linux

Person 5 -- Preferred OS: macOS | Ubuntu | Arch Linux
----> Laptop ID: 14 -- OS: Ubuntu

Person 6 -- Preferred OS: Arch Linux | Ubuntu
----> Laptop ID: 3 -- OS: Arch Linux

Person 7 -- Preferred OS: macOS
----> Laptop ID: 11 -- OS: macOS

Person 8 -- Preferred OS: macOS
----> Laptop ID: 16 -- OS: macOS

Person 12 -- Preferred OS: Arch Linux | macOS | Ubuntu
----> Laptop ID: 6 -- OS: Arch Linux

Person 13 -- Preferred OS: Arch Linux
----> Laptop ID: 10 -- OS: Arch Linux

Person 14 -- Preferred OS: Ubuntu | Arch Linux | macOS
----> Laptop ID: 5 -- OS: Ubuntu

Person 15 -- Preferred OS: Ubuntu | macOS | Arch Linux
----> Laptop ID: 7 -- OS: Ubuntu

Person 16 -- Preferred OS: macOS | Arch Linux | Ubuntu
----> Laptop ID: 17 -- OS: Ubuntu

Person 18 -- Preferred OS: Ubuntu | macOS | Arch Linux
----> Laptop ID: 9 -- OS: Ubuntu

Person 19 -- Preferred OS: Arch Linux | Ubuntu | macOS
----> Laptop ID: 13 -- OS: Arch Linux

Person 20 -- Preferred OS: Arch Linux | Ubuntu | macOS
----> Laptop ID: 15 -- OS: Arch Linux

Person 21 -- Preferred OS: Ubuntu
----> Laptop ID: 12 -- OS: Ubuntu

1 change: 1 addition & 0 deletions implement-laptop-allocation/requirements.txt
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scipy>=1.13.1
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