From ec893ea84c2ec15ec4e07ddfb7cf797919dc2e20 Mon Sep 17 00:00:00 2001 From: Danila Kuzmin Date: Fri, 25 Sep 2026 23:45:58 +0300 Subject: [PATCH 1/2] Solve task 1 --- src/part1/constants.py | 22 ++++++++++++--------- src/part1/snowflake.py | 43 ++++++++++++++++++++++++++++++------------ 2 files changed, 44 insertions(+), 21 deletions(-) diff --git a/src/part1/constants.py b/src/part1/constants.py index 9abfbba2..e731519a 100644 --- a/src/part1/constants.py +++ b/src/part1/constants.py @@ -15,24 +15,28 @@ 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] = (1 << TIMESTAMP_BITS) - 1 +NODE_ID_MAX: Final[int] = (1 << NODE_ID_BITS) - 1 +SEQUENCE_ID_MAX: Final[int] = (1 << 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 + +NS_PER_MS: Final[int] = 1_000_000 diff --git a/src/part1/snowflake.py b/src/part1/snowflake.py index d3abf050..9dbec27d 100644 --- a/src/part1/snowflake.py +++ b/src/part1/snowflake.py @@ -13,14 +13,17 @@ :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_DEFAULT, NODE_ID_MAX, + NODE_ID_SHIFT, + NS_PER_MS, SEQUENCE_ID_MAX, TIMESTAMP_MS_MAX, + TIMESTAMP_SHIFT, ) @@ -34,8 +37,9 @@ 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 + + current_ms = time.time_ns() // NS_PER_MS + return current_ms - epoch_ms def decode_timestamp_ms(snowflake_id: int, epoch_ms: int = EPOCH_MS_DEFAULT) -> int: @@ -50,8 +54,9 @@ 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 + + delta_ms = (snowflake_id >> TIMESTAMP_SHIFT) & TIMESTAMP_MS_MAX + return delta_ms + epoch_ms def decode_node_id(snowflake_id: int) -> int: @@ -64,8 +69,8 @@ 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 >> NODE_ID_SHIFT) & NODE_ID_MAX def decode_sequence_id(snowflake_id: int) -> int: @@ -78,8 +83,8 @@ 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 +115,19 @@ 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 node_id < 0 or node_id > NODE_ID_MAX: + print(f"node_id must be in [0, {NODE_ID_MAX}], got {node_id}") + return None + + if sequence_id < 0 or sequence_id > SEQUENCE_ID_MAX: + print(f"sequence_id must be in [0, {SEQUENCE_ID_MAX}], got {sequence_id}") + return None + + timestamp_ms = read_current_millis(epoch_ms) + + if timestamp_ms > TIMESTAMP_MS_MAX: + print(f"timestamp {timestamp_ms} overflows {TIMESTAMP_MS_MAX}") + return None + + return (timestamp_ms << TIMESTAMP_SHIFT) | (node_id << NODE_ID_SHIFT) | sequence_id From a3395abbcf6676085608e585f6134010199b874b Mon Sep 17 00:00:00 2001 From: magistralik111 Date: Fri, 2 Oct 2026 23:29:12 +0300 Subject: [PATCH 2/2] Solve task 2 --- .DS_Store | Bin 0 -> 6148 bytes src/.DS_Store | Bin 0 -> 6148 bytes src/part2/cart.py | 94 +++++++++++++++++++++++++++++++++++++++---- src/part2/crud.py | 60 +++++++++++++++++++++------ src/part2/storage.py | 10 ++--- src/part2/utils.py | 11 +++-- 6 files changed, 143 insertions(+), 32 deletions(-) create mode 100644 .DS_Store create mode 100644 src/.DS_Store diff --git a/.DS_Store b/.DS_Store new file mode 100644 index 0000000000000000000000000000000000000000..55da4264e32167c7a0cf8b8ff45f18094829ae7d GIT binary patch literal 6148 zcmeHKyJ`bL3>?LV7}B^*xxbJXO@{7{C`c-P6|kYf2Dvew=dfbU#WWQ?B%@IHu@{wYtD2xu7ko5 m?U)$tm>X}$k5QC$&DVV13#Y`OGaq!Keg<3@nH2bI1-=3J-Wo6f literal 0 HcmV?d00001 diff --git a/src/.DS_Store b/src/.DS_Store new file mode 100644 index 0000000000000000000000000000000000000000..f580346f806ff0f586d968d16c8911cd47ef2ddd GIT binary patch literal 6148 zcmeH~J&pn~427Q;R$6HrO3E}GfEz@JJpmWsuS8$Msy6h=2%)fCz|y z2#kn89O69xzen^;dK3{5fpHMOV literal 0 HcmV?d00001 diff --git a/src/part2/cart.py b/src/part2/cart.py index 063f9aea..ffd0cb78 100644 --- a/src/part2/cart.py +++ b/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 +22,38 @@ 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 find_cart_line(cart: list[CartLine], product_id: int) -> CartLine | None: + + for line in cart: + if product_id == line[LINE_PRODUCT_ID_INDEX]: + return line + + return None + + +def change_cart_quantity( + cart: list[CartLine], product_id: int, quantity: int +) -> CartLine: + + new_line = (product_id, quantity) + line = find_cart_line(cart, product_id) + + if line is None: + cart.append(new_line) + return new_line + + position = cart.index(line) + + if quantity == 0: + cart.pop(position) + else: + cart[position] = new_line + + return new_line def add_to_cart( @@ -53,8 +82,32 @@ 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 product is None: + return None + + if product[QUANTITY_INDEX] < quantity: + print( + f"not enough stock for product {product_id}: {product[QUANTITY_INDEX]} available, {quantity} requested" + ) + return None + + update_product( + storage, + product_id, + (product[NAME_INDEX], product[PRICE_INDEX], product[QUANTITY_INDEX] - quantity), + ) + + line = find_cart_line(cart, product_id) + + if line is None: + return change_cart_quantity(cart, product_id, quantity) + + new_quantity = line[LINE_QUANTITY_INDEX] + quantity + + return change_cart_quantity(cart, product_id, new_quantity) def remove_from_cart( @@ -85,5 +138,30 @@ 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) + + line = find_cart_line(cart, product_id) + + if line is None: + print(f"product {product_id} is not in the cart") + return None + + if line[LINE_QUANTITY_INDEX] < quantity: + print( + f"cart holds only {line[LINE_QUANTITY_INDEX]} unit(s) of product {product_id}, cannot remove {quantity}" + ) + return None + + product = read_product(storage, product_id) + + if product is None: + return None + + update_product( + storage, + product_id, + (product[NAME_INDEX], product[PRICE_INDEX], product[QUANTITY_INDEX] + quantity), + ) + + new_quantity = line[LINE_QUANTITY_INDEX] - quantity + + return change_cart_quantity(cart, product_id, new_quantity) diff --git a/src/part2/crud.py b/src/part2/crud.py index d026cbcb..f6cd6d4a 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 +34,11 @@ 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 + + return max(product[PRODUCT_ID_INDEX] for product in storage) + 1 def create_product( @@ -56,8 +59,18 @@ 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 + + product_id = generate_product_id(storage) + storage.append((product_id, name, normalize_price(price), quantity)) + + return product_id def read_product(storage: list[Product], product_id: int) -> Product | None: @@ -72,8 +85,14 @@ 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) + + for product in storage: + if product_id == product[PRODUCT_ID_INDEX]: + return product + + print(f"no product with id {product_id}") + + return None def update_product( @@ -99,8 +118,18 @@ 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) + + product = read_product(storage, product_id) + + if product is None: + return None + + name, price, quantity = fields + updated_product = (product_id, name, normalize_price(price), quantity) + position = storage.index(product) + storage[position] = updated_product + + return updated_product def delete_product(storage: list[Product], product_id: int) -> int | None: @@ -116,5 +145,12 @@ 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 + + product = read_product(storage, product_id) + + if product is None: + return None + + storage.remove(product) + + return product_id diff --git a/src/part2/storage.py b/src/part2/storage.py index b63d5fc7..e4bceff1 100644 --- a/src/part2/storage.py +++ b/src/part2/storage.py @@ -24,11 +24,9 @@ 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 +NAME_INDEX: Final = 1 +PRICE_INDEX: Final = 2 +QUANTITY_INDEX: Final = 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..fa159f32 100644 --- a/src/part2/utils.py +++ b/src/part2/utils.py @@ -6,13 +6,12 @@ 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(1).scaleb(-PRICE_PRECISION) def normalize_price(price: Decimal) -> Decimal: @@ -25,5 +24,5 @@ def normalize_price(price: Decimal) -> Decimal: ``price`` quantised to :data:`PRICE_PRECISION` fractional digits, with halves rounded up. """ - # TODO: реализуйте функцию - return Decimal(0) + + return price.quantize(PRICE_STEP, rounding=ROUND_HALF_UP)