Initial course version

[Polina (polinak1r)]

This PR contains a first complete version of the course with a brief introduction.

• All tasks have been added and are now present in the course structure
• All placeholders have been filled in and checked for correctness
• Both unit tests and hidden tests run correctly for all tasks

[Konstantin Chaika (kochaika)]

Perhaps these comments apply to other tasks as well.
Roman Kovalev (@KovalevRoma) pay attention to it too

[Konstantin Chaika (kochaika)]

from bisect import bisect_left, bisect_right
from sys import stdin

Imports are missing

[Konstantin Chaika (kochaika)]

Am I correct in understanding that stdin.read() will keep reading as long as there is data to read, and if I run this in an IDE (click run button) and enter data manually, the input will never finish?

[Konstantin Chaika (kochaika)]

NameError: name 'product' is not defined

[Konstantin Chaika (kochaika)]

Traceback (most recent call last):
  File "/Users/Konstantin.Chaika/PycharmProjects/algorithmic-toolbox-python/L03/T04/tests/tests.py", line 12, in test_random_pairs
    self.assertEqual(a * b // math.gcd(a, b), lcm(a, b), msg=f"Wrong answer for a={a}, b={b}")
                                              ^^^^^^^^^
  File "/Users/Konstantin.Chaika/PycharmProjects/algorithmic-toolbox-python/L03/T04/lcm.py", line 12, in lcm
    assert 1 <= a <= 2 * 10 ** 9 and 1 <= b <= 2 * 10 ** 9
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError

[Konstantin Chaika (kochaika)]

[Konstantin Chaika (kochaika)]

Maybe assert inside the lcm function is not a thing we should use here
Or at least do not call it from tests with invalid inputs

[Roman Kovalev (KovalevRoma)]

Environment

• OS: Windows 11 / Ubuntu 22.04
• IDE: PyCharm 2026.1.1
• Python 3.10, Python 3.13

Issues

1. Overall potential issue:

In all tasks, the algorithmic complexity is not actually being tested. As a result, naive solutions pass all tests. This should be fixed. This is especially important for tasks where asymptotic optimization is explicitly required: L05/T02, L05/T04.

2. L02/T02 (Maximum Pairwise Product)

• The task title appears twice in the description.

• The solution in the course differs from the one in solution:
  • solution uses an O(n log n) approach (sorting)
  • the original solution works in O(n):

    a = 0
    b = 0
    for i in range(len(numbers)):
        if numbers[i] > a:
            b = a
            a = numbers[i]
        elif numbers[i] > b:
            b = numbers[i]
    return a * b

• This does not affect correctness for small inputs, but there are no large tests where the difference is noticeable. When a student opens "peek solution", this inconsistency may be confusing.

---

3. L03/T01 (Fibonacci Number)

• The task title is duplicated in the description.

---

4. L04/T03 (Maximum Value of the Loot)

• The task title is duplicated in the description.

Notes:

L03/T02 (Last Digit of Fibonacci Number)

• The peek solution is not optimal in terms of memory usage.
• It would be better to adapt the solution from L03/T01 using O(1) memory:

  previous, current = current, (previous + current) % 10

• Since this is an algorithms course, the peek solution should demonstrate an optimal approach.

[Konstantin Chaika (kochaika)]

Ctrl + D does not work on MacOS when app is run inside the IDE. With green triangle button click
But it do work in the terminal

When app is run inside the IDE Cmd + D works...
¯\_(ツ)_/¯

[Konstantin Chaika (kochaika)]

Need to be removed: Sasha will publish it from his own vendor!