diff --git a/laptop_allocation.py b/laptop_allocation.py
new file mode 100644
index 000000000..589d39183
--- /dev/null
+++ b/laptop_allocation.py
@@ -0,0 +1,191 @@
+from dataclasses import dataclass, field
+from enum import Enum
+from typing import Dict, List
+
+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_system: List[OperatingSystem]
+    
+    def __hash__(self):
+        return hash((self.name, self.age))
+
+
+@dataclass(frozen=True)
+class Laptop:
+    id: int
+    manufacturer: str
+    model: str
+    screen_size_in_inches: float
+    operating_system: OperatingSystem
+    
+def allocate_laptops(people: List[Person], laptops: List[Laptop]) -> Dict[Person, Laptop]:
+    if len(people) > len(laptops):
+        raise Exception("Sorry, there are not enough laptops.")
+    alloc_dict = {}
+    # people with fewer options choose first, because they potentially can generate most sadness
+    people.sort(key=lambda person: len(person.preferred_operating_system))
+    for person in people:
+        for laptop in laptops:
+            is_match = False
+            # if it a last chance to get a laptop, it used anyway 
+            if laptops.index(laptop) == len(laptops) - 1:
+                alloc_dict[person] = laptop
+                break
+            for sys in person.preferred_operating_system:
+                if sys == laptop.operating_system:
+                    alloc_dict[person] = laptop
+                    laptops.pop(laptops.index(laptop))
+                    is_match = True
+                    break
+            if is_match:
+                break
+    return alloc_dict
+    
+def calcSadness(person: Person, laptop: Laptop) -> int:
+    sadness = 0
+    is_sys_matched = False
+    for i in range(len(person.preferred_operating_system)):
+        if person.preferred_operating_system[i] == laptop.operating_system:
+            is_sys_matched = True
+            sadness += i
+            break
+    if not is_sys_matched:
+        sadness = 100
+    return sadness
+
+def print_allocation(alloc_dict: Dict[Person, Laptop]) -> None:
+    for person in alloc_dict.keys():
+        print(f"{person.name} gets: {alloc_dict[person].model} with {alloc_dict[person].operating_system.name}.")
+
+def main() -> None:
+    people_five = [
+        Person(name="Alice", age=28, 
+            preferred_operating_system=[OperatingSystem.MACOS, OperatingSystem.UBUNTU]),
+        Person(name="Bob", age=34, 
+            preferred_operating_system=[OperatingSystem.ARCH]),
+        Person(name="Charlie", age=22, 
+            preferred_operating_system=[OperatingSystem.ARCH, OperatingSystem.UBUNTU, OperatingSystem.MACOS]),
+        Person( name="Dana", age=41, 
+            preferred_operating_system=[OperatingSystem.MACOS]),
+        Person(name="Eli", age=25, 
+            preferred_operating_system=[OperatingSystem.ARCH, OperatingSystem.MACOS])
+    ]
+    laptops_five = [
+        Laptop(id=1, manufacturer="Apple", model="MacBook Pro 14", screen_size_in_inches=14.2, operating_system=OperatingSystem.MACOS),
+        Laptop(id=2, manufacturer="Framework", model="Laptop 13", screen_size_in_inches=13.5, operating_system=OperatingSystem.ARCH),
+        Laptop(id=3, manufacturer="Dell", model="XPS 13 Developer Edition", screen_size_in_inches=13.4, operating_system=OperatingSystem.UBUNTU),
+        Laptop(id=4, manufacturer="Apple", model="MacBook Air", screen_size_in_inches=13.6, operating_system=OperatingSystem.MACOS),
+        Laptop(id=5, manufacturer="Lenovo", model="ThinkPad X1 Carbon", screen_size_in_inches=14.0, operating_system=OperatingSystem.ARCH)
+    ]
+    people_ten = [
+        Person(name="Alice", age=28, 
+            preferred_operating_system=[OperatingSystem.MACOS, OperatingSystem.UBUNTU]),
+        Person(name="Bob", age=34, 
+            preferred_operating_system=[OperatingSystem.ARCH]),
+        Person(name="Charlie", age=22, 
+            preferred_operating_system=[OperatingSystem.ARCH, OperatingSystem.UBUNTU, OperatingSystem.MACOS]),
+        Person( name="Dana", age=41, 
+            preferred_operating_system=[OperatingSystem.MACOS]),
+        Person(name="Eli", age=25, 
+            preferred_operating_system=[OperatingSystem.ARCH, OperatingSystem.MACOS]),
+        Person(name="Fiona", age=30, 
+            preferred_operating_system=[OperatingSystem.UBUNTU, OperatingSystem.ARCH]),
+        Person(name="George", age=27, 
+            preferred_operating_system=[OperatingSystem.MACOS, OperatingSystem.ARCH]),
+        Person(name="Hannah", age=29, 
+            preferred_operating_system=[OperatingSystem.ARCH]),
+        Person(name="Ian", age=38, 
+            preferred_operating_system=[OperatingSystem.MACOS, OperatingSystem.UBUNTU]),
+        Person(name="Julia", age=24, 
+            preferred_operating_system=[OperatingSystem.ARCH, OperatingSystem.UBUNTU])
+    ]
+    laptops_ten = [
+        Laptop(id=1, manufacturer="Apple", model="MacBook Pro 14", screen_size_in_inches=14.2, operating_system=OperatingSystem.MACOS),
+        Laptop(id=2, manufacturer="Framework", model="Laptop 13", screen_size_in_inches=13.5, operating_system=OperatingSystem.ARCH),
+        Laptop(id=3, manufacturer="Dell", model="XPS 13 Developer Edition", screen_size_in_inches=13.4, operating_system=OperatingSystem.UBUNTU),
+        Laptop(id=4, manufacturer="Apple", model="MacBook Air", screen_size_in_inches=13.6, operating_system=OperatingSystem.MACOS),
+        Laptop(id=5, manufacturer="Lenovo", model="ThinkPad X1 Carbon", screen_size_in_inches=14.0, operating_system=OperatingSystem.ARCH),
+        Laptop(id=6, manufacturer="System76", model="Lemur Pro", screen_size_in_inches=14.1, operating_system=OperatingSystem.UBUNTU),
+        Laptop(id=7, manufacturer="Apple", model="MacBook Pro 16", screen_size_in_inches=16.2, operating_system=OperatingSystem.MACOS),
+        Laptop(id=8, manufacturer="Razer", model="Blade 14", screen_size_in_inches=14.0, operating_system=OperatingSystem.ARCH),
+        Laptop(id=9, manufacturer="HP", model="Dev One", screen_size_in_inches=14.0, operating_system=OperatingSystem.UBUNTU),
+        Laptop(id=10, manufacturer="ASUS", model="ROG Zephyrus G14", screen_size_in_inches=14.0, operating_system=OperatingSystem.ARCH)
+    ]
+    laptops_twenty = [
+        Laptop(1, "Apple", "MacBook Pro 14", 14.2, OperatingSystem.MACOS),
+        Laptop(2, "Framework", "Laptop 13", 13.5, OperatingSystem.ARCH),
+        Laptop(3, "Dell", "XPS 13", 13.4, OperatingSystem.UBUNTU),
+        Laptop(4, "Apple", "MacBook Air M3", 13.6, OperatingSystem.MACOS),
+        Laptop(5, "Lenovo", "ThinkPad X1 Carbon", 14.0, OperatingSystem.ARCH),
+        Laptop(6, "System76", "Lemur Pro", 14.1, OperatingSystem.UBUNTU),
+        Laptop(7, "Apple", "MacBook Pro 16", 16.2, OperatingSystem.MACOS),
+        Laptop(8, "Razer", "Blade 14", 14.0, OperatingSystem.ARCH),
+        Laptop(9, "HP", "Dev One", 14.0, OperatingSystem.UBUNTU),
+        Laptop(10, "ASUS", "ROG Zephyrus G14", 14.0, OperatingSystem.ARCH),
+        Laptop(11, "Apple", "MacBook Air M2", 15.3, OperatingSystem.MACOS),
+        Laptop(12, "Star Labs", "StarBook", 14.0, OperatingSystem.ARCH),
+        Laptop(13, "Lenovo", "ThinkPad P16", 16.0, OperatingSystem.UBUNTU),
+        Laptop(14, "Microsoft", "Surface Laptop (Linux Mod)", 13.5, OperatingSystem.ARCH),
+        Laptop(15, "Apple", "MacBook Pro 13", 13.3, OperatingSystem.MACOS),
+        Laptop(16, "Framework", "Laptop 16", 16.0, OperatingSystem.ARCH),
+        Laptop(17, "Dell", "Precision 5570", 15.6, OperatingSystem.UBUNTU),
+        Laptop(18, "System76", "Pangolin", 15.6, OperatingSystem.UBUNTU),
+        Laptop(19, "Apple", "MacBook Air", 13.3, OperatingSystem.MACOS),
+        Laptop(20, "Tuxedo", "InfinityBook Pro", 14.0, OperatingSystem.ARCH)
+    ]
+    people_twenty = [
+        Person("Alice", 25, [OperatingSystem.ARCH]),
+        Person("Bob", 32, [OperatingSystem.MACOS, OperatingSystem.UBUNTU]),
+        Person("Charlie", 19, [OperatingSystem.ARCH, OperatingSystem.UBUNTU]),
+        Person("Diana", 45, [OperatingSystem.MACOS]),
+        Person("Edward", 28, [OperatingSystem.ARCH, OperatingSystem.MACOS, OperatingSystem.UBUNTU]),
+        Person("Fiona", 31, [OperatingSystem.UBUNTU, OperatingSystem.ARCH]),
+        Person("George", 27, [OperatingSystem.ARCH]),
+        Person("Hannah", 22, [OperatingSystem.MACOS, OperatingSystem.ARCH]),
+        Person("Ian", 35, [OperatingSystem.MACOS]),
+        Person("Julia", 29, [OperatingSystem.ARCH, OperatingSystem.MACOS]),
+        Person("Kevin", 24, [OperatingSystem.ARCH]),
+        Person("Laura", 33, [OperatingSystem.MACOS, OperatingSystem.UBUNTU]),
+        Person("Mason", 26, [OperatingSystem.ARCH, OperatingSystem.UBUNTU, OperatingSystem.MACOS]),
+        Person("Nora", 40, [OperatingSystem.MACOS]),
+        Person("Oliver", 21, [OperatingSystem.ARCH]),
+        Person("Paige", 30, [OperatingSystem.UBUNTU]),
+        Person("Quinn", 23, [OperatingSystem.ARCH, OperatingSystem.MACOS]),
+        Person("Riley", 38, [OperatingSystem.MACOS, OperatingSystem.UBUNTU]),
+        Person("Sam", 25, [OperatingSystem.ARCH]),
+        Person("Tina", 29, [OperatingSystem.MACOS, OperatingSystem.ARCH])
+    ]
+    # inside allocation function .pop() function is used when laptop selected - 
+    # so copy of original list is passed to avoid mutation
+    result_dict_5 = allocate_laptops(people=people_five, laptops=laptops_five.copy())
+    result_dict_10 = allocate_laptops(people=people_ten, laptops=laptops_ten.copy())
+    result_dict_20 = allocate_laptops(people=people_twenty, laptops=laptops_twenty.copy())
+    print("####################################result for 5 people and 5 laptops#####################################")
+    print_allocation(alloc_dict=result_dict_5)
+    sadness_5 = 0
+    for person in result_dict_5.keys():
+        sadness_5 += calcSadness(person, result_dict_5[person])
+    print(f"Total sadness: {sadness_5}")
+    print("###################################result for 10 people and 10 laptops####################################")
+    print_allocation(alloc_dict=result_dict_10)
+    sadness_10 = 0
+    for person in result_dict_10.keys():
+        sadness_10 += calcSadness(person, result_dict_10[person])
+    print(f"Total sadness: {sadness_10}")
+    print("###################################result for 20 people and 20 laptops####################################")
+    print_allocation(alloc_dict=result_dict_20)
+    sadness_20 = 0
+    for person in result_dict_20.keys():
+        sadness_20 += calcSadness(person, result_dict_20[person])
+    print(f"Total sadness: {sadness_20}")
+
+if __name__ == "__main__":
+    main()
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