From 8668211fb8c20db131a4cb85f179a945fdd5bcc3 Mon Sep 17 00:00:00 2001
From: Nataliia Volkova <volkov.nataliia@gmail.com>
Date: Wed, 19 Nov 2025 12:51:34 +0000
Subject: [PATCH 1/8] 01 Implement shell tools (cat, ls, wc) in JS with mode

---
 implement-shell-tools/cat/cat.js | 33 +++++++++++++++++++
 implement-shell-tools/ls/ls.js   | 56 ++++++++++++++++++++++++++++++++
 implement-shell-tools/wc/wc.js   | 38 ++++++++++++++++++++++
 3 files changed, 127 insertions(+)
 create mode 100644 implement-shell-tools/cat/cat.js
 create mode 100644 implement-shell-tools/ls/ls.js
 create mode 100644 implement-shell-tools/wc/wc.js

diff --git a/implement-shell-tools/cat/cat.js b/implement-shell-tools/cat/cat.js
new file mode 100644
index 000000000..331be0929
--- /dev/null
+++ b/implement-shell-tools/cat/cat.js
@@ -0,0 +1,33 @@
+import process from "node:process";
+import { promises as fs } from "node:fs";
+
+const arrArgv = process.argv.slice(2);
+
+const numberLines = arrArgv.includes("-n");
+const numberNonemptyLines = arrArgv.includes("-b");
+
+const nonFlagArrArgv = arrArgv.filter((arr) => !arr.startsWith("-"));
+
+let number = 1;
+
+for (let file of nonFlagArrArgv) {
+  const content = await fs.readFile(file, "utf-8");
+
+  const linedText = content.split("\n");
+
+  const numbered = linedText.map((line) => {
+    if (numberNonemptyLines) {
+      if (line.trim() === "") {
+        return line;
+      } else {
+        return `${String(number++).padStart(3)}  ${line}`;
+      }
+    }
+    if (numberLines) {
+      return `${String(number++).padStart(3)}  ${line}`;
+    }
+
+    return line;
+  });
+  console.log(numbered.join("\n"));
+}
diff --git a/implement-shell-tools/ls/ls.js b/implement-shell-tools/ls/ls.js
new file mode 100644
index 000000000..47414da60
--- /dev/null
+++ b/implement-shell-tools/ls/ls.js
@@ -0,0 +1,56 @@
+import process from "node:process";
+import { promises as fs } from "node:fs";
+import path from "node:path";
+
+const arrArgv = process.argv.slice(2);
+
+const longFormat = arrArgv.includes("-l");
+const showHidden = arrArgv.includes("-a");
+
+const paths = arrArgv.filter((argv) => !argv.startsWith("-"));
+if (paths.length === 0) path = "[.]";
+
+for (let listFile of paths) {
+  const status = await fs.stat(listFile);
+
+  if (status.isFile()) {
+    const permissions = (status.mode & 0o777).toString(8);
+    const sizeFile = status.size;
+    const owner = status.uid;
+    const group = status.gid;
+    const timeMod = status.mtime.toLocaleString();
+
+    if (longFormat) {
+      console.log(
+        `${permissions}, ${owner}, ${group}, ${sizeFile}, ${timeMod}, ${listFile}`
+      );
+    } else {
+      console.log(listFile);
+    }
+  } else {
+    let files = await fs.readdir(listFile, { withFileTypes: true });
+
+    if (!showHidden) {
+      files = files.filter((file) => !file.name.startsWith("."));
+    }
+
+    for (let file of files) {
+      const wholePath = path.join(listFile, file.name);
+      const statusFile = await fs.stat(wholePath);
+
+      const permissions = (statusFile.mode & 0o777).toString(8);
+      const sizeFile = statusFile.size;
+      const owner = statusFile.uid;
+      const group = statusFile.gid;
+      const timeMod = statusFile.mtime.toLocaleString();
+
+      if (longFormat) {
+        console.log(
+          `${permissions}, ${owner}, ${group}, ${sizeFile}, ${timeMod}, ${file.name}`
+        );
+      } else {
+        console.log(file.name);
+      }
+    }
+  }
+}
diff --git a/implement-shell-tools/wc/wc.js b/implement-shell-tools/wc/wc.js
new file mode 100644
index 000000000..2648d62d3
--- /dev/null
+++ b/implement-shell-tools/wc/wc.js
@@ -0,0 +1,38 @@
+import process from "node:process";
+import { promises as fs } from "node:fs";
+
+const arrArgv = process.argv.slice(2);
+
+const lines = arrArgv.includes("-l");
+const words = arrArgv.includes("-w");
+const bytes = arrArgv.includes("-c");
+
+const noFlags = !lines && !words && !bytes;
+
+const paths = arrArgv.filter((argv) => !argv.startsWith("-"));
+
+for (let path of paths) {
+  const context = await fs.readFile(path, "utf-8");
+
+  const countLines = context.split(/\r?\n/).length;
+  const countWords = context.split(/\s+/).length;
+  const countBytes = Buffer.byteLength(context, "utf-8");
+
+  let startInput = "";
+
+  if (noFlags || lines) {
+    startInput += `${countLines} `;
+  }
+
+  if (noFlags || words) {
+    startInput += `${countWords} `;
+  }
+
+  if (noFlags || bytes) {
+    startInput += `${countBytes} `;
+  }
+
+  startInput += path;
+
+  console.log(startInput);
+}

From 061be3093946f3ce3eb7f41b56fcd9b1fcb40f38 Mon Sep 17 00:00:00 2001
From: Nataliia Volkova <volkov.nataliia@gmail.com>
Date: Sat, 20 Dec 2025 19:05:36 +0000
Subject: [PATCH 2/8] python script allocation laptop

---
 allocate_laptop.py | 91 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 91 insertions(+)
 create mode 100644 allocate_laptop.py

diff --git a/allocate_laptop.py b/allocate_laptop.py
new file mode 100644
index 000000000..3a842d9dc
--- /dev/null
+++ b/allocate_laptop.py
@@ -0,0 +1,91 @@
+from dataclasses import dataclass
+from enum import Enum
+from typing import List, Dict, Tuple, Optional
+
+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: List[OperatingSystem]
+
+
+@dataclass(frozen=True)
+class Laptop:
+    id: int
+    manufacturer: str
+    model: str
+    screen_size_in_inches: float
+    operating_system: OperatingSystem
+
+def norm_os_values(value: str) -> OperatingSystem:
+    value = value.strip().lower()
+    if value == "ubuntu":
+        return OperatingSystem.UBUNTU
+    if value == "arch linux":
+        return OperatingSystem.ARCH
+    if value == "macos":
+        return OperatingSystem.MACOS
+    raise ValueError(f"Unknown OS: {value}")
+
+
+people = [
+    Person(name="Imran", age=22, preferred_operating_systems=[norm_os_values("Ubuntu"), norm_os_values("Arch Linux")]),
+    Person(name="Eliza", age=34, preferred_operating_systems=[norm_os_values("Arch Linux"), norm_os_values("macOS"), norm_os_values("Ubuntu")]),
+    Person(name="Ira", age=21, preferred_operating_systems=[norm_os_values("Ubuntu"), norm_os_values("Arch Linux")]),
+    Person(name="Anna", age=34, preferred_operating_systems=[norm_os_values("Ubuntu"), norm_os_values("macOS")]),
+    Person(name="Nahimn", age=42, preferred_operating_systems=[norm_os_values("Ubuntu"), norm_os_values("Arch Linux")])
+]
+
+laptops = [
+    Laptop(id=1, manufacturer="Dell", model="XPS", screen_size_in_inches=13, operating_system=norm_os_values("Arch Linux")),
+    Laptop(id=2, manufacturer="Dell", model="XPS", screen_size_in_inches=15, operating_system=norm_os_values("Ubuntu")),
+    Laptop(id=3, manufacturer="Dell", model="XPS", screen_size_in_inches=15, operating_system=norm_os_values("ubuntu")),
+    Laptop(id=4, manufacturer="Apple", model="macBook", screen_size_in_inches=13, operating_system=norm_os_values("macOS")),
+]
+
+
+def allocate_laptops(people: List[Person], laptops: List[Laptop]) -> Dict[Tuple[str, int], int]:
+    sadness_table: Dict[Tuple[str, int], int] = {}
+    for person in people:
+        for laptop in laptops:
+            if laptop.operating_system in person.preferred_operating_systems:
+                index = person.preferred_operating_systems.index(laptop.operating_system)
+                sadness = index
+            else:
+                sadness = 100
+            sadness_table[(person.name, laptop.id)] = sadness
+    return sadness_table
+
+
+sadness_table = allocate_laptops(people, laptops)
+
+allocation_list: List[Tuple[str, Optional[int], int]] = []
+allocated_laptops: set[int] = set()
+allocated_persons: set[str] = set()
+total_happiness: int = 0
+
+for (person_name, laptop_id), sadness in sorted(sadness_table.items(), key=lambda value: value[1]):
+    if laptop_id in allocated_laptops:
+        continue
+    if person_name in allocated_persons:
+        continue
+    allocation_list.append((person_name, laptop_id, sadness))
+    allocated_laptops.add(laptop_id)
+    allocated_persons.add(person_name)
+    total_happiness += sadness
+    print(f"{person_name} got laptop {laptop_id}")
+
+    
+for person in people:
+    if person.name not in allocated_persons:
+        print(f"{person.name} did not get laptop")
+print(f"Total happiness: {total_happiness}")
+
+print(allocation_list)
+

From eb8a06bf350ae74baa648f28503fcb8d96fd7747 Mon Sep 17 00:00:00 2001
From: Nataliia Volkova <volkov.nataliia@gmail.com>
Date: Sat, 20 Dec 2025 19:34:52 +0000
Subject: [PATCH 3/8] Inheritens

---
 inherit.py | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 inherit.py

diff --git a/inherit.py b/inherit.py
new file mode 100644
index 000000000..f0675ef48
--- /dev/null
+++ b/inherit.py
@@ -0,0 +1,39 @@
+from typing import List
+
+class Parent:
+    def __init__(self, first_name: str, last_name: str):
+        self.first_name = first_name
+        self.last_name = last_name
+
+    def get_name(self) -> str:
+        return f"{self.first_name} {self.last_name}"
+
+
+class Child(Parent):
+    def __init__(self, first_name: str, last_name: str):
+        super().__init__(first_name, last_name)
+        self.previous_last_names: List [str]= []
+
+    def change_last_name(self, last_name: str) -> None:
+        self.previous_last_names.append(self.last_name)
+        self.last_name = last_name
+
+    def get_full_name(self) -> str:
+        suffix: str = ""
+        if len(self.previous_last_names) > 0:
+            suffix = f" (née {self.previous_last_names[0]})"
+        return f"{self.first_name} {self.last_name}{suffix}"
+
+person1 = Child("Elizaveta", "Alekseeva")
+print(person1.get_name())
+print(person1.get_full_name())
+person1.change_last_name("Tyurina")
+print(person1.get_name())
+print(person1.get_full_name())
+
+person2 = Parent("Elizaveta", "Alekseeva")
+print(person2.get_name())
+# print(person2.get_full_name())  // this method dose not belong to Parent class
+# person2.change_last_name("Tyurina") // this method dose not belong to Parent class
+print(person2.get_name())
+# print(person2.get_full_name()) // this method dose not belong to Parent class
\ No newline at end of file

From 5f5269349384c9237e7e7f2e90ab0da308ca5340 Mon Sep 17 00:00:00 2001
From: Nataliia Volkova <volkov.nataliia@gmail.com>
Date: Sat, 20 Dec 2025 19:46:34 +0000
Subject: [PATCH 4/8] enum exer.

---
 enums.py | 105 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 105 insertions(+)
 create mode 100644 enums.py

diff --git a/enums.py b/enums.py
new file mode 100644
index 000000000..2a776b917
--- /dev/null
+++ b/enums.py
@@ -0,0 +1,105 @@
+from dataclasses import dataclass
+from enum import Enum
+from typing import List, Dict
+import sys
+
+
+
+
+class OperatingSystem(Enum):
+    MACOS = "macOS"
+    ARCH = "Arch Linux"
+    UBUNTU = "Ubuntu"
+
+@dataclass(frozen=True)
+class Person:
+    name:  str
+    age: int
+    preferred_operating_system: OperatingSystem
+
+
+@dataclass(frozen=True)
+class Laptop:
+    id: int
+    manufacturer: str
+    model: str
+    screen_size_in_inches: float
+    operating_system: OperatingSystem
+
+
+def count_laptops(laptops: List[Laptop]) -> Dict[OperatingSystem, int]:
+    number_eachOS_laptops: Dict[OperatingSystem, int] = {
+        OperatingSystem.MACOS: 0,
+        OperatingSystem.ARCH: 0,
+        OperatingSystem.UBUNTU: 0}
+    for laptop in laptops:
+        number_eachOS_laptops[laptop.operating_system] +=1
+    return number_eachOS_laptops
+
+
+def count_possible_laptops(laptops: List[Laptop], person: Person) -> int:
+    possible_laptops: List[Laptop] =[]
+    for laptop in laptops:
+        if laptop.operating_system == person.preferred_operating_system:
+            possible_laptops.append(laptop)
+    number_possible_laptops = len(possible_laptops)
+    return number_possible_laptops
+
+def chose_alternative_laptops(laptops: List[Laptop], person: Person) -> Dict[OperatingSystem, int]:
+    number_possible_laptops = count_possible_laptops(laptops, person)
+    number_eachOS_laptops = count_laptops(laptops)
+    preferred_os = person.preferred_operating_system
+    alternative_laptops: Dict[OperatingSystem, int] = {}
+    for eachOS, count in number_eachOS_laptops.items():
+        if eachOS == preferred_os:
+            continue
+        if count > number_possible_laptops:
+            alternative_laptops[eachOS] = count
+    if len(alternative_laptops) != 0:
+        print(f"There is an operating system that has more laptops available.If you’re willing to accept them, there is a list: {alternative_laptops}.")
+        return alternative_laptops
+    else:
+        print("There is not an operating system that has more laptops available.")
+        return alternative_laptops
+
+while True:
+    user_name = input("Type your name: ").strip()
+    if len(user_name) < 3:
+        print(f"Error, {user_name} is not valid. Try again, length should be more than 3 characters.")
+        continue
+    break
+
+while True:
+    user_age = input("Type your age: ").strip()
+    try:
+        user_age_int = int(user_age)
+        if user_age_int < 18:
+            raise ValueError
+        break
+    except ValueError:
+        print("Invalid age, try again! Borrowing allowed from 18 years old.")
+
+available_os = [os.value for os in OperatingSystem]
+print("Available OSs are: ", ",".join(available_os))
+user_operating_system = input("Type operating system: ").strip()
+if user_operating_system not in available_os:
+    print(f"Error, {user_operating_system} is not in available list\n"
+    f"Available OSs are: {','.join(available_os)}", file=sys.stderr)
+    sys.exit(1)
+
+preferred_operating_system = OperatingSystem(user_operating_system)
+
+user = Person(name=user_name, age=user_age_int, preferred_operating_system=preferred_operating_system)
+
+
+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),
+]
+
+
+possible_laptops = count_possible_laptops(laptops, user)
+print(f"Possible laptops for {user_name}: {possible_laptops}")
+alternative_laptops = chose_alternative_laptops(laptops, user)

From 762ed73eb70c096c6440e28efe0b2da64785e3ba Mon Sep 17 00:00:00 2001
From: Nataliia Volkova <volkov.nataliia@gmail.com>
Date: Sat, 20 Dec 2025 19:54:53 +0000
Subject: [PATCH 5/8] typy guide refactoring

---
 type_guide_refact.py | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)
 create mode 100644 type_guide_refact.py

diff --git a/type_guide_refact.py b/type_guide_refact.py
new file mode 100644
index 000000000..f1ee15eb3
--- /dev/null
+++ b/type_guide_refact.py
@@ -0,0 +1,42 @@
+from dataclasses import dataclass
+from typing import List
+
+@dataclass(frozen=True)
+class Person:
+    name: str
+    age: int
+    preferred_operating_systems: List[str]
+
+
+@dataclass(frozen=True)
+class Laptop:
+    id: int
+    manufacturer: str
+    model: str
+    screen_size_in_inches: float
+    operating_system: str
+
+
+def find_possible_laptops(laptops: List[Laptop], person: Person) -> List[Laptop]:
+    possible_laptops: list[Laptop] = []
+    for laptop in laptops:
+        if laptop.operating_system in person.preferred_operating_systems:
+            possible_laptops.append(laptop)
+    return possible_laptops
+
+
+people = [
+    Person(name="Imran", age=22, preferred_operating_systems=["Ubuntu"]),
+    Person(name="Eliza", age=34, preferred_operating_systems=["Arch Linux"]),
+]
+
+laptops = [
+    Laptop(id=1, manufacturer="Dell", model="XPS", screen_size_in_inches=13, operating_system="Arch Linux"),
+    Laptop(id=2, manufacturer="Dell", model="XPS", screen_size_in_inches=15, operating_system="Ubuntu"),
+    Laptop(id=3, manufacturer="Dell", model="XPS", screen_size_in_inches=15, operating_system="ubuntu"),
+    Laptop(id=4, manufacturer="Apple", model="macBook", screen_size_in_inches=13, operating_system="macOS"),
+]
+
+for person in people:
+    possible_laptops = find_possible_laptops(laptops, person)
+    print(f"Possible laptops for {person.name}: {possible_laptops}")
\ No newline at end of file

From 7e620980463ddd41f65aee94eda46bde028448b0 Mon Sep 17 00:00:00 2001
From: Nataliia Volkova <volkov.nataliia@gmail.com>
Date: Sat, 20 Dec 2025 20:02:10 +0000
Subject: [PATCH 6/8] generics

---
 familytree.py | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)
 create mode 100644 familytree.py

diff --git a/familytree.py b/familytree.py
new file mode 100644
index 000000000..2e2579d69
--- /dev/null
+++ b/familytree.py
@@ -0,0 +1,20 @@
+from dataclasses import dataclass
+from typing import List
+
+@dataclass(frozen=True)
+class Person:
+    name: str
+    children: List["Person"]
+    age: int
+
+fatma = Person(name="Fatma", children=[], age=17)
+aisha = Person(name="Aisha", children=[], age=25)
+
+imran = Person(name="Imran", children=[fatma, aisha], age=51)
+
+def print_family_tree(person: Person) -> None:
+    print(person.name, f"({person.age})")
+    for child in person.children:
+        print(f"- {child.name} ({child.age})")
+
+print_family_tree(imran)
\ No newline at end of file

From 63309c281205879e3f03a707142d687b2409805c Mon Sep 17 00:00:00 2001
From: Nataliia Volkova <volkov.nataliia@gmail.com>
Date: Sat, 20 Dec 2025 20:10:41 +0000
Subject: [PATCH 7/8] dataclasses

---
 dataclasses_ex.py | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)
 create mode 100644 dataclasses_ex.py

diff --git a/dataclasses_ex.py b/dataclasses_ex.py
new file mode 100644
index 000000000..0114071a2
--- /dev/null
+++ b/dataclasses_ex.py
@@ -0,0 +1,24 @@
+from datetime import date
+from dataclasses import dataclass
+
+@dataclass(frozen=True)
+class Person:
+        name: str
+        preferred_operating_system: str
+        birth_date: date
+
+        def is_adult(self) -> bool:
+            today = date.today()
+            age = today.year - self.birth_date.year
+
+            if (today.month, today.day) < (self.birth_date.month, self.birth_date.day):
+                age -=1
+                
+            return age >= 18
+
+imran = Person("Imran", "Ubuntu", date(2000, 9, 12))
+
+print(imran.is_adult())
+
+
+

From 12748b0a1a43cc43c99e8510e5e6e356c54c735e Mon Sep 17 00:00:00 2001
From: Nataliia Volkova <volkov.nataliia@gmail.com>
Date: Sat, 20 Dec 2025 20:54:09 +0000
Subject: [PATCH 8/8] types_banc_account_exer

---
 typesExer.py | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 typesExer.py

diff --git a/typesExer.py b/typesExer.py
new file mode 100644
index 000000000..9ba857ef1
--- /dev/null
+++ b/typesExer.py
@@ -0,0 +1,33 @@
+from typing import Union, Dict
+
+
+def open_account(balances: Dict[str, int], name: str, amount: Union[str, float]):
+    balances[name] = int(float(amount) *100)
+
+def sum_balances(accounts: Dict[str, int]):
+    total = 0
+    for name, pence in accounts.items():
+        print(f"{name} had balance {pence}")
+        total += pence
+    return total
+
+def format_pence_as_pound(total_pence: int) -> str:
+    if total_pence < 100:
+        return f"{total_pence}p"
+    pounds = total_pence // 100
+    pence = total_pence % 100
+    return f"£{pounds}.{pence:02d}"
+
+balances = {
+    "Sima": 700,
+    "Linn": 545,
+    "Georg": 831,
+}
+
+open_account(balances, "Tobi", 9.13)
+open_account(balances, "Olya", 7.13)
+
+total_pence = sum_balances(balances)
+total_pound = format_pence_as_pound(total_pence)
+
+print(f"The bank accounts total {total_pound}")
\ No newline at end of file