WestMidlands| SDC-NOV-2025| Sara Tahir| Sprint 5| Feature/laptop allocation

laptopAllocation/.vscode/settings.json

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+{
+    "python-envs.pythonProjects": []
+}

laptopAllocation/laptop.py

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+from dataclasses import dataclass
+from enum import Enum
+from typing import Dict, List
+import numpy as np  #to build and mnaiplate our sadness grid
+from scipy.optimize import linear_sum_assignment #to find optimal laptop allocaation to minimize sadness across all users
+
+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]
+
+
+@dataclass(frozen=True)
+class Laptop:
+    id: int
+    manufacturer: str
+    model: str
+    screen_size_in_inches: float
+    operating_system: OperatingSystem
+
+#library of laptops
+laptops = [
+    Laptop(id=1, manufacturer="Dell", model="XPS", screen_size_in_inches=13, operating_system=OperatingSystem.ARCH),
+    Laptop(id=2, manufacturer="Dell", model="XPS", screen_size_in_inches=15, operating_system=OperatingSystem.UBUNTU),
+    Laptop(id=3, manufacturer="Dell", model="XPS", screen_size_in_inches=15, operating_system=OperatingSystem.UBUNTU),
+    Laptop(id=4, manufacturer="Apple", model="macBook", screen_size_in_inches=13, operating_system=OperatingSystem.MACOS),
+    Laptop(id=5, manufacturer="Apple", model="macBook", screen_size_in_inches=13, operating_system=OperatingSystem.MACOS),
+    Laptop(id=6, manufacturer="Dell", model="macBook", screen_size_in_inches=13, operating_system=OperatingSystem.ARCH),
+    Laptop(id=7, manufacturer="Apple", model="macBook", screen_size_in_inches=13, operating_system=OperatingSystem.MACOS),
+    Laptop(id=8, manufacturer="Apple", model="macBook", screen_size_in_inches=13, operating_system=OperatingSystem.MACOS),
+]
+# Preset dataset of people
+people = [
+    Person(name="Sara", age=31, preferred_operating_systems=(OperatingSystem.ARCH,OperatingSystem.UBUNTU)),
+    Person(name="Shabs", age=40, preferred_operating_systems=(OperatingSystem.ARCH,OperatingSystem.MACOS,OperatingSystem.UBUNTU)),
+    Person(name="Jawad", age= 36, preferred_operating_systems=(OperatingSystem.MACOS,OperatingSystem.UBUNTU,OperatingSystem.ARCH)),    
+    Person(name="Mike", age=35, preferred_operating_systems=(OperatingSystem.MACOS,OperatingSystem.ARCH)),
+    Person(name="Mawra", age=28, preferred_operating_systems=(OperatingSystem.MACOS,)),#adding a comma for one item tuple
+    Person(name="Fatma", age= 22, preferred_operating_systems=(OperatingSystem.UBUNTU,OperatingSystem.ARCH)),    
+    Person(name="Muhib", age= 19, preferred_operating_systems=(OperatingSystem.MACOS,OperatingSystem.UBUNTU)),    
+
+]
+
+
+# Updated based on feedback: 
+# Instead of hard‑coding sadness scores (0, 1, 2), this version uses the 
+# position of the laptop’s OS in the person’s preference list to decide the sadness value. 
+# I check for membership first (so no exceptions), then 
+# use the index as the rank. Only the top MAX_HAPPY_RANK preferences count; 
+# anything lower or not listed gets a high penalty. 
+
+MAX_HAPPY_RANK = 3
+TERRIBLE_SADNESS = 100
+def sadness(person: Person, laptop: Laptop) -> int:
+    prefs = person.preferred_operating_systems
+
+    if laptop.operating_system not in prefs:
+        return TERRIBLE_SADNESS
+
+    rank = prefs.index(laptop.operating_system)
+
+    return rank if rank < MAX_HAPPY_RANK else TERRIBLE_SADNESS
+
+    #Allocate laptops to people in a way that minimises total sadness.
+    #Builds a cost matrix using the sadness() function and applies the
+    #Hungarian algorithm (linear_sum_assignment) to find the optimal
+    #one‑to‑one assignment between people and laptops.
+
+
+def allocate_laptops(people: List[Person], laptops: List[Laptop]) -> Dict[Person, Laptop]:
+    n_people = len(people) #length of people []
+    n_laptops = len(laptops) #length of laptops []
+    if n_laptops < n_people:
+        raise ValueError("Not enough laptops to allocate one to each person.")
+    sadness_matrix = np.zeros((n_people, n_laptops), dtype= int)  #npzero mean each cell in 2d grid is a zero and dtype is datatype int so it int 0
+    for i, person in enumerate(people): #enumerate gives us both index position and the item itself from the list 
+        for j, laptop in enumerate(laptops):
+            sadness_matrix[i,j] = sadness(person, laptop) #this matrix represents complete laptop allocation 
+            # Hungarian algorithm to run on our sadness matrix
+    row_indices, col_indices = linear_sum_assignment(sadness_matrix) #which person which laptop
+        # Map people to laptops
+    allocation: Dict[Person, Laptop] = {}
+    for i, j in zip(row_indices, col_indices):#it pairs up results (person indices and laptop indices). The loop then uses those pairs to build the final allocation dictionary
+        allocation[people[i]] = laptops[j]
+    return allocation
+
+
+def print_allocation(allocation: Dict[Person, Laptop]):
+    for person, lap in allocation.items():
+        print(f"{person.name} gets Laptop {lap.id} ({lap.operating_system.value})")
+
+allocation = allocate_laptops(people, laptops)
+print_allocation(allocation)

laptopAllocation/pytest.ini

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+[pytest]
+pythonpath = .

laptopAllocation/tests/test_laptop.py

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+
+#If a person gets a laptop with their first‑choice operating system, their sadness should be 0.
+from laptop import Person, Laptop, OperatingSystem, sadness
+
+def test_sadness_first_choice():
+    person = Person("Test", 20, (OperatingSystem.MACOS,))
+    laptop = Laptop(1, "Apple", "macBook", 13, OperatingSystem.MACOS)
+
+    assert sadness(person, laptop) == 0
+from laptop import Person, Laptop, OperatingSystem, sadness, TERRIBLE_SADNESS
+#Adding more tests 
+def test_sadness_second_choice():
+    person = Person("Test", 20, (OperatingSystem.MACOS, OperatingSystem.UBUNTU))
+    laptop = Laptop(1, "Dell", "XPS", 13, OperatingSystem.UBUNTU)
+    assert sadness(person, laptop) == 1
+
+
+def test_sadness_not_in_preferences():
+    person = Person("Test", 20, (OperatingSystem.MACOS,))
+    laptop = Laptop(1, "Dell", "XPS", 13, OperatingSystem.UBUNTU)
+    assert sadness(person, laptop) == TERRIBLE_SADNESS
+
+
+def test_sadness_above_max_rank():
+    # as our MAX_HAPPY_RANK = 3, so rank 3 should be TERRIBLE_SADNESS
+    person = Person(
+        "Test", 20,
+        (OperatingSystem.MACOS, OperatingSystem.UBUNTU, OperatingSystem.ARCH)
+    )
+    laptop = Laptop(1, "Dell", "XPS", 13, OperatingSystem.ARCH)
+    assert sadness(person, laptop) == TERRIBLE_SADNESS