From ec87df07ffb41d5fc27ee153fd1136224570b719 Mon Sep 17 00:00:00 2001 From: samirhappy Date: Fri, 25 Sep 2026 18:38:55 +0300 Subject: [PATCH 1/3] Implement part 1 snowflake --- src/part1/constants.py | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) diff --git a/src/part1/constants.py b/src/part1/constants.py index 9abfbba2..2cc5954b 100644 --- a/src/part1/constants.py +++ b/src/part1/constants.py @@ -19,20 +19,22 @@ # 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). +NODE_ID_SHIFT: Final[int] = SEQUENCE_ID_BITS +TIMESTAMP_SHIFT: Final[int] = NODE_ID_BITS + SEQUENCE_ID_BITS From eb01c003631cec1484d420d7b4f873b7906b43f7 Mon Sep 17 00:00:00 2001 From: samirhappy Date: Fri, 25 Sep 2026 22:51:58 +0300 Subject: [PATCH 2/3] Implement snowflake generator --- src/part1/snowflake.py | 34 ++++++++++++++++++++++------------ 1 file changed, 22 insertions(+), 12 deletions(-) diff --git a/src/part1/snowflake.py b/src/part1/snowflake.py index d3abf050..0bb11774 100644 --- a/src/part1/snowflake.py +++ b/src/part1/snowflake.py @@ -13,14 +13,16 @@ :func:`decode_node_id` and :func:`decode_sequence_id`. """ -import time # noqa: F401 +from time import time -from .constants import ( # noqa: F401 +from .constants import ( EPOCH_MS_DEFAULT, NODE_ID_DEFAULT, NODE_ID_MAX, + NODE_ID_SHIFT, SEQUENCE_ID_MAX, TIMESTAMP_MS_MAX, + TIMESTAMP_SHIFT, ) @@ -34,8 +36,7 @@ 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 int(time() * 1000 - epoch_ms) def decode_timestamp_ms(snowflake_id: int, epoch_ms: int = EPOCH_MS_DEFAULT) -> int: @@ -50,8 +51,7 @@ 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 + return (snowflake_id >> TIMESTAMP_SHIFT) + epoch_ms def decode_node_id(snowflake_id: int) -> int: @@ -64,8 +64,7 @@ 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 >> NODE_ID_SHIFT) & NODE_ID_MAX def decode_sequence_id(snowflake_id: int) -> int: @@ -78,8 +77,7 @@ 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( @@ -110,5 +108,17 @@ def generate_snowflake_id( 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}], got {node_id}") + return None + + if not (0 <= sequence_id <= SEQUENCE_ID_MAX): + print(f"sequence_id must be in [0, {SEQUENCE_ID_MAX}], got {sequence_id}") + return None + + elapsed_ms = read_current_millis(epoch_ms) + if elapsed_ms > TIMESTAMP_MS_MAX: + print("overflows") + return None + + return (elapsed_ms << TIMESTAMP_SHIFT) | (node_id << NODE_ID_SHIFT) | sequence_id From c540069beba70225a3bb11712a9fa326f661aa31 Mon Sep 17 00:00:00 2001 From: samirhappy Date: Fri, 2 Oct 2026 22:05:29 +0300 Subject: [PATCH 3/3] task 2 --- src/part2/cart.py | 70 +++++++++++++++++++++++++++++++++++++------- src/part2/crud.py | 53 +++++++++++++++++++++++++-------- src/part2/storage.py | 10 +++---- src/part2/utils.py | 8 ++--- 4 files changed, 108 insertions(+), 33 deletions(-) diff --git a/src/part2/cart.py b/src/part2/cart.py index 063f9aea..1d3f7f43 100644 --- a/src/part2/cart.py +++ b/src/part2/cart.py @@ -11,11 +11,8 @@ from typing import Final -from .crud import read_product, update_product # noqa: F401 -from .storage import ( # noqa: F401 - NAME_INDEX, - PRICE_INDEX, - QUANTITY_INDEX, +from .crud import read_product, update_product +from .storage import ( Product, ) @@ -23,8 +20,8 @@ type CartLine = tuple[int, int] # TODO: задайте позиции полей внутри кортежа CartLine -LINE_PRODUCT_ID_INDEX: Final = 0 -LINE_QUANTITY_INDEX: Final = 0 +LINE_PRODUCT_ID_INDEX: Final[int] = 0 +LINE_QUANTITY_INDEX: Final[int] = 1 def add_to_cart( @@ -53,8 +50,30 @@ 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) + product = read_product(storage, product_id) + if not product: + return None + + _, name, price, stock_quantity = product + if stock_quantity < quantity: + print( + f"Not enough stock for product {product_id}: " + f"{stock_quantity} available, {quantity} requested" + ) + return None + + update_product(storage, product_id, (name, price, stock_quantity - quantity)) + + for i in range(len(cart)): + if cart[i][LINE_PRODUCT_ID_INDEX] == product_id: + cart_quantity = cart[i][LINE_QUANTITY_INDEX] + new_line = (product_id, cart_quantity + quantity) + cart[i] = new_line + return new_line + + new_line = (product_id, quantity) + cart.append(new_line) + return new_line def remove_from_cart( @@ -85,5 +104,34 @@ 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) + for i in range(len(cart)): + if cart[i][LINE_PRODUCT_ID_INDEX] == product_id: + cart_quantity = cart[i][LINE_QUANTITY_INDEX] + if quantity > cart_quantity: + print( + f"Cart holds only {cart_quantity} units of product {product_id}, " + f"cannot remove {quantity}" + ) + return None + + product = read_product(storage, product_id) + if not product: + return None + + _, name, price, stock_quantity = product + update_product( + storage, + product_id, + (name, price, stock_quantity + quantity), + ) + + remaining_quantity = cart_quantity - quantity + if remaining_quantity == 0: + del cart[i] + return (product_id, 0) + + cart[i] = (product_id, remaining_quantity) + return cart[i] + + print(f"Product {product_id} is not in the cart") + return None diff --git a/src/part2/crud.py b/src/part2/crud.py index d026cbcb..0bfe0959 100644 --- a/src/part2/crud.py +++ b/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 +34,14 @@ 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 not storage: + return PRODUCT_ID_MIN + + max_id = 0 + for product in storage: + current_id = int(product[PRODUCT_ID_INDEX]) + max_id = max(current_id, max_id) + return max_id + 1 def create_product( @@ -56,8 +62,16 @@ def create_product( ``storage`` is left unchanged and a message naming the clashing name is printed. """ - # TODO: реализуйте функцию - return 0 + name, price, quantity = fields + for product in storage: + if product[NAME_INDEX] == name: + print(f"Product name '{name}' is already taken") + return None + + new_id = generate_product_id(storage) + normalized_price = normalize_price(price) + storage.append((new_id, name, normalized_price, quantity)) + return new_id def read_product(storage: list[Product], product_id: int) -> Product | None: @@ -65,15 +79,17 @@ def read_product(storage: list[Product], product_id: int) -> Product | None: Args: storage: The product store to search. - product_id: The identifier to look up. Returns: The matching ``(product_id, name, price, quantity)`` record, or ``None`` when no product carries that identifier (a message is printed in that case). """ - # TODO: реализуйте функцию - return (0, "", Decimal(0), 0) + for product in storage: + if product[PRODUCT_ID_INDEX] == product_id: + return product + print(f"No product with id {product_id}") + return None def update_product( @@ -99,8 +115,15 @@ 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) + name, price, quantity = fields + normalized_price = normalize_price(price) + for i in range(len(storage)): + if storage[i][PRODUCT_ID_INDEX] == product_id: + updated_product = (product_id, name, normalized_price, quantity) + storage[i] = updated_product + return updated_product + print(f"No product with id {product_id}") + return None def delete_product(storage: list[Product], product_id: int) -> int | None: @@ -116,5 +139,9 @@ 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 + for i in range(len(storage)): + if storage[i][PRODUCT_ID_INDEX] == product_id: + del storage[i] + return product_id + print(f"No product with id {product_id}") + return None diff --git a/src/part2/storage.py b/src/part2/storage.py index b63d5fc7..73cc4464 100644 --- a/src/part2/storage.py +++ b/src/part2/storage.py @@ -25,10 +25,10 @@ type Product = tuple[int, str, Decimal, int] # TODO: задайте позиции полей внутри кортежа Product -PRODUCT_ID_INDEX: Final = 0 -NAME_INDEX: Final = 0 -PRICE_INDEX: Final = 0 -QUANTITY_INDEX: Final = 0 +PRODUCT_ID_INDEX: Final[int] = 0 +NAME_INDEX: Final[int] = 1 +PRICE_INDEX: Final[int] = 2 +QUANTITY_INDEX: Final[int] = 3 # TODO: задайте идентификатор первого товара в пустом хранилище -PRODUCT_ID_MIN: Final[int] = 0 +PRODUCT_ID_MIN: Final[int] = 1 diff --git a/src/part2/utils.py b/src/part2/utils.py index ec0348d3..528429ef 100644 --- a/src/part2/utils.py +++ b/src/part2/utils.py @@ -6,13 +6,13 @@ currency values free of binary floating-point error. """ -from decimal import ROUND_HALF_UP, Decimal # noqa: F401 +from decimal import ROUND_HALF_UP, Decimal from typing import Final # TODO: задайте число знаков после запятой и шаг квантования -PRICE_PRECISION: Final[int] = 0 -PRICE_STEP: Final = Decimal(0) +PRICE_PRECISION: Final[int] = 2 +PRICE_STEP: Final[Decimal] = Decimal(1).scaleb(-PRICE_PRECISION) def normalize_price(price: Decimal) -> Decimal: @@ -26,4 +26,4 @@ def normalize_price(price: Decimal) -> Decimal: with halves rounded up. """ # TODO: реализуйте функцию - return Decimal(0) + return price.quantize(PRICE_STEP, rounding=ROUND_HALF_UP)