1. Горнаков Алексей Владимирович. 612

.vscode/settings.json

@@ -0,0 +1,4 @@
+{
+    "python-envs.defaultEnvManager": "ms-python.python:conda",
+    "python-envs.defaultPackageManager": "ms-python.python:conda"
+}

fix_and_test.sh

@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+# Auto-fix imports/format, then run tests.
+set -euo pipefail
+
+cd "$(dirname "$0")"
+
+if ! command -v uv >/dev/null 2>&1; then
+    echo "Error: uv is not installed. Install it: https://docs.astral.sh/uv/getting-started/installation/" >&2
+    exit 1
+fi
+
+echo "==> Install dependencies"
+uv sync --locked
+
+echo "==> Ruff fix (imports, lint)"
+uv run ruff check --fix src
+uv run ruff format src
+
+# echo "==> Pytest"
+# uv run pytest src/part3/tests
+
+echo "All done."

pyproject.toml

@@ -10,6 +10,7 @@ dependencies = []
 dev = [
     "mypy==2.3.1",
     "ruff==0.16.8",
+    "pytest>=9.1.1",
 ]
 
 [tool.ruff]
@@ -33,3 +34,13 @@ avoid-escape = true
 [tool.ruff.lint.isort]
 lines-after-imports = 2
 split-on-trailing-comma = true
+
+[tool.mypy]
+strict = true
+files = ["src"]
+mypy_path = "src"
+explicit_package_bases = true
+
+[tool.pytest.ini_options]
+pythonpath = ["src"]
+testpaths = ["src/tests"]

src/part1/constants.py

@@ -1,38 +1,21 @@
-"""Bit layout and default epoch for the Twitter Snowflake ID generator.
-
-A Snowflake identifier is a 63-bit positive integer packed as follows, from
-the most significant bit downwards:
-
-    1 bit   unused sign bit, always zero
-    41 bits milliseconds elapsed since a custom epoch
-    10 bits node identifier
-    12 bits per-millisecond sequence counter
-
-The shift and mask constants should be derived from the bit widths so that
-changing a width keeps everything else consistent.
-"""
-
 from typing import Final
 
 
-# TODO: замените заглушки (0) на корректные значения, см. TASK.md.
-# Все константы, зависящие от ёмкостей *_BITS, должны вычисляться из них.
-
 # Twitter's original Snowflake epoch: 2010-11-04 01:42:54.657 UTC.
-EPOCH_MS_DEFAULT: Final[int] = 0
+EPOCH_MS_DEFAULT: Final[int] = 1288834974657
 
 # Node identifier used when the caller does not supply one.
-NODE_ID_DEFAULT: Final[int] = 0
+NODE_ID_DEFAULT: Final[int] = 1
 
 # Width of each field, in bits.
-TIMESTAMP_BITS: Final[int] = 0
-NODE_ID_BITS: Final[int] = 0
-SEQUENCE_ID_BITS: Final[int] = 0
+TIMESTAMP_BITS: Final[int] = 41
+NODE_ID_BITS: Final[int] = 10
+SEQUENCE_ID_BITS: Final[int] = 12
 
 # Largest value each field can hold.
-TIMESTAMP_MS_MAX: Final[int] = 0
-NODE_ID_MAX: Final[int] = 0
-SEQUENCE_ID_MAX: Final[int] = 0
+TIMESTAMP_MS_MAX: Final[int] = 2**TIMESTAMP_BITS - 1
+NODE_ID_MAX: Final[int] = 2**NODE_ID_BITS - 1
+SEQUENCE_ID_MAX: Final[int] = 2**SEQUENCE_ID_BITS - 1
 
 # Здесь можно добавить собственные вспомогательные константы
 # (например, сдвиги полей при сборке идентификатора).

src/part1/snowflake.py

@@ -13,13 +13,16 @@
 :func:`decode_node_id` and :func:`decode_sequence_id`.
 """
 
-import time  # noqa: F401
+import time
 
-from .constants import (  # noqa: F401
+from .constants import (
     EPOCH_MS_DEFAULT,
+    NODE_ID_BITS,
     NODE_ID_DEFAULT,
     NODE_ID_MAX,
+    SEQUENCE_ID_BITS,
     SEQUENCE_ID_MAX,
+    TIMESTAMP_BITS,
     TIMESTAMP_MS_MAX,
 )
 
@@ -34,8 +37,7 @@ def read_current_millis(epoch_ms: int) -> int:
         The count of whole milliseconds between ``epoch_ms`` and now. May be
         negative if ``epoch_ms`` lies in the future.
     """
-    # TODO: реализуйте функцию
-    return 0
+    return time.time_ns() // 10**6 - epoch_ms
 
 
 def decode_timestamp_ms(snowflake_id: int, epoch_ms: int = EPOCH_MS_DEFAULT) -> int:
@@ -50,8 +52,9 @@ def decode_timestamp_ms(snowflake_id: int, epoch_ms: int = EPOCH_MS_DEFAULT) ->
         The absolute Unix time in milliseconds at which the identifier was
         generated.
     """
-    # TODO: реализуйте функцию
-    return 0
+    del_time = (snowflake_id >> (NODE_ID_BITS + TIMESTAMP_BITS)) & TIMESTAMP_MS_MAX
+
+    return epoch_ms + del_time
 
 
 def decode_node_id(snowflake_id: int) -> int:
@@ -64,8 +67,8 @@ def decode_node_id(snowflake_id: int) -> int:
         The node identifier packed into ``snowflake_id``, in the range
         ``[0, NODE_ID_MAX]``.
     """
-    # TODO: реализуйте функцию
-    return 0
+
+    return (snowflake_id >> SEQUENCE_ID_BITS) & NODE_ID_MAX
 
 
 def decode_sequence_id(snowflake_id: int) -> int:
@@ -78,37 +81,28 @@ def decode_sequence_id(snowflake_id: int) -> int:
         The per-millisecond sequence counter packed into ``snowflake_id``, in
         the range ``[0, SEQUENCE_ID_MAX]``.
     """
-    # TODO: реализуйте функцию
-    return 0
+    return snowflake_id & SEQUENCE_ID_MAX
 
 
 def generate_snowflake_id(
     sequence_id: int,
     node_id: int = NODE_ID_DEFAULT,
     epoch_ms: int = EPOCH_MS_DEFAULT,
 ) -> int | None:
-    """Build and return a Snowflake identifier for the current millisecond.
-
-    The function is stateless: the caller passes the per-millisecond sequence
-    counter explicitly. It is the caller's responsibility to increment
-    ``sequence_id`` for identifiers minted within the same millisecond and to
-    reset it once the clock advances.
-
-    Args:
-        sequence_id: The per-millisecond sequence counter, in the range
-            ``[0, SEQUENCE_ID_MAX]``.
-        node_id: The identifier of this node, in the range ``[0, NODE_ID_MAX]``.
-            Optional; defaults to ``NODE_ID_DEFAULT``.
-        epoch_ms: The start of the epoch as Unix milliseconds. Optional;
-            defaults to the original Twitter epoch (2010-11-04 01:42:54.657
-            UTC).
-
-    Returns:
-        The Snowflake identifier as a positive 63-bit integer, or ``None`` if
-        ``node_id`` is outside ``[0, NODE_ID_MAX]``, ``sequence_id`` is outside
-        ``[0, SEQUENCE_ID_MAX]``, or the elapsed time no longer fits in the
-        timestamp field (roughly 69 years after ``epoch_ms``). In each of those
-        cases an explanatory message is printed to stdout first.
-    """
-    # TODO: реализуйте функцию
-    return 0
+    if not (0 <= node_id <= NODE_ID_MAX):
+        print(f"node_id must be in [0, {NODE_ID_MAX}]. Your id {node_id}")
+        return None
+    elif not (0 <= sequence_id <= SEQUENCE_ID_MAX):
+        print(f"sequence_id must be in [0, {SEQUENCE_ID_MAX}] Your id {sequence_id}")
+        return None
+
+    else:
+        if 0 <= epoch_ms <= TIMESTAMP_MS_MAX:
+            return (
+                epoch_ms
+                << (SEQUENCE_ID_BITS + NODE_ID_BITS) + node_id
+                << SEQUENCE_ID_BITS + sequence_id
+            )
+        else:
+            print("overflows")
+            return None

src/part2/cart.py

@@ -11,8 +11,8 @@
 
 from typing import Final
 
-from .crud import read_product, update_product  # noqa: F401
-from .storage import (  # noqa: F401
+from .crud import read_product, update_product
+from .storage import (
     NAME_INDEX,
     PRICE_INDEX,
     QUANTITY_INDEX,
@@ -22,9 +22,9 @@
 
 type CartLine = tuple[int, int]
 
-# TODO: задайте позиции полей внутри кортежа CartLine
+
 LINE_PRODUCT_ID_INDEX: Final = 0
-LINE_QUANTITY_INDEX: Final = 0
+LINE_QUANTITY_INDEX: Final = 1
 
 
 def add_to_cart(
@@ -53,8 +53,31 @@ def add_to_cart(
         The cart line for ``product_id`` after the addition, or ``None``
         when the product is unknown or the store cannot cover the request.
     """
-    # TODO: реализуйте функцию
-    return (0, 0)
+    search = read_product(storage, product_id)
+    if search == None:
+        return None
+    elif search[QUANTITY_INDEX] < quantity:
+        print(
+            f"not enough stock for product {product_id}: {search[NAME_INDEX]} available, {search[QUANTITY_INDEX]} requested"
+        )
+        return None
+
+    update_product(
+        storage,
+        product_id,
+        (search[NAME_INDEX], search[PRICE_INDEX], search[QUANTITY_INDEX] - quantity),
+    )
+
+    cart_search_l = [el for el in cart if el[LINE_PRODUCT_ID_INDEX] == product_id]
+    cart_search = cart_search_l[0]
+    if cart_search:
+        new_cart_line = (product_id, cart_search[LINE_QUANTITY_INDEX] + quantity)
+        cart.remove(cart_search)
+        cart.append(new_cart_line)
+        return new_cart_line
+    else:
+        cart.append((product_id, quantity))
+        return (product_id, quantity)
 
 
 def remove_from_cart(
@@ -85,5 +108,35 @@ def remove_from_cart(
         zero means the line was dropped), or ``None`` when the cart has no
         line for the product or holds too few units.
     """
-    # TODO: реализуйте функцию
-    return (0, 0)
+    search_l = [el for el in cart if el[LINE_PRODUCT_ID_INDEX] == product_id]
+    search = search_l[0]
+    if not search:
+        print(f"product {product_id} is not in the cart")
+        return None
+    elif search[LINE_QUANTITY_INDEX] < quantity:
+        print(
+            f"cart holds only {search[LINE_QUANTITY_INDEX]} unit(s) of product {product_id}, cannot remove {quantity}"
+        )
+        return None
+
+    search_storage = read_product(storage, product_id)
+    if search_storage == None:
+        return None
+
+    update_product(
+        storage,
+        product_id,
+        (
+            search_storage[NAME_INDEX],
+            search_storage[PRICE_INDEX],
+            (search_storage[QUANTITY_INDEX] + quantity),
+        ),
+    )
+
+    if quantity == search[LINE_QUANTITY_INDEX]:
+        cart.remove(search)
+        return (product_id, 0)
+
+    new_line = (product_id, search[LINE_QUANTITY_INDEX] - quantity)
+    cart[cart.index(search)] = new_line
+    return new_line

src/part2/crud.py

@@ -14,13 +14,13 @@
 
 from decimal import Decimal
 
-from .storage import (  # noqa: F401
+from .storage import (
     NAME_INDEX,
     PRODUCT_ID_INDEX,
     PRODUCT_ID_MIN,
     Product,
 )
-from .utils import normalize_price  # noqa: F401
+from .utils import normalize_price
 
 
 def generate_product_id(storage: list[Product]) -> int:
@@ -34,8 +34,12 @@ def generate_product_id(storage: list[Product]) -> int:
         :data:`~src.part2.storage.PRODUCT_ID_MIN` when ``storage`` is
         empty.
     """
-    # TODO: реализуйте функцию
-    return 0
+    if storage:
+        id: int = max(tuple(el[PRODUCT_ID_INDEX] for el in storage)) + 1
+    else:
+        id = PRODUCT_ID_MIN
+
+    return id
 
 
 def create_product(
@@ -56,8 +60,12 @@ def create_product(
         ``storage`` is left unchanged and a message naming the clashing
         name is printed.
     """
-    # TODO: реализуйте функцию
-    return 0
+    if fields[NAME_INDEX - 1] in tuple(el[NAME_INDEX] for el in storage):
+        print(f"product name {fields[0]} is already taken")
+        return None
+    id = generate_product_id(storage)
+    storage.append((id, fields[0], normalize_price(fields[1]), fields[2]))
+    return id
 
 
 def read_product(storage: list[Product], product_id: int) -> Product | None:
@@ -72,8 +80,11 @@ def read_product(storage: list[Product], product_id: int) -> Product | None:
         ``None`` when no product carries that identifier (a message is
         printed in that case).
     """
-    # TODO: реализуйте функцию
-    return (0, "", Decimal(0), 0)
+    if product_id not in tuple(el[PRODUCT_ID_INDEX] for el in storage):
+        print(f"no product with id {product_id}")
+        return None
+
+    return next(filter(lambda x: x[PRODUCT_ID_INDEX], storage))
 
 
 def update_product(
@@ -99,8 +110,14 @@ def update_product(
         ``None`` when no product carries that identifier (``storage`` is
         left unchanged and a message is printed).
     """
-    # TODO: реализуйте функцию
-    return (0, "", Decimal(0), 0)
+    search = read_product(storage, product_id)
+    if search == None:
+        print(f"no product with id {product_id}")
+        return None
+
+    storage[storage.index(search)] = (product_id,) + fields
+
+    return next(filter(lambda x: x[PRODUCT_ID_INDEX] == product_id, storage))
 
 
 def delete_product(storage: list[Product], product_id: int) -> int | None:
@@ -116,5 +133,9 @@ def delete_product(storage: list[Product], product_id: int) -> int | None:
         product carried that identifier (``storage`` is left unchanged and
         a message is printed).
     """
-    # TODO: реализуйте функцию
-    return 0
+    if not filter(lambda x: x[PRODUCT_ID_INDEX] == product_id, storage):
+        print(f"no product with id {product_id}")
+        return None
+
+    storage.remove(next(filter(lambda x: x[PRODUCT_ID_INDEX] == product_id, storage)))
+    return product_id