From e16319f4cdd0e6a02f0a02943773b1d61b34239d Mon Sep 17 00:00:00 2001 From: alpen9 Date: Fri, 25 Sep 2026 20:49:03 +0300 Subject: [PATCH 01/11] task --- src/part1/constants.py | 19 +++++++++++-------- src/part1/snowflake.py | 34 ++++++++++++++++++++++++++-------- 2 files changed, 37 insertions(+), 16 deletions(-) diff --git a/src/part1/constants.py b/src/part1/constants.py index 9abfbba2..bff179aa 100644 --- a/src/part1/constants.py +++ b/src/part1/constants.py @@ -19,20 +19,23 @@ # 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). +SEQUENCE_ID_SHIFT: Final[int] = 0 # справа(младшие разряды) +NODE_ID_SHIFT: Final[int] = SEQUENCE_ID_BITS +TIMESTAMP_SHIFT: Final[int] = SEQUENCE_ID_BITS + NODE_ID_BITS diff --git a/src/part1/snowflake.py b/src/part1/snowflake.py index d3abf050..0a09b53b 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, + SEQUENCE_ID_BITS, SEQUENCE_ID_MAX, TIMESTAMP_MS_MAX, + TIMESTAMP_SHIFT, ) @@ -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 int(time.time() * 1000) - epoch_ms def decode_timestamp_ms(snowflake_id: int, epoch_ms: int = EPOCH_MS_DEFAULT) -> int: @@ -51,7 +53,8 @@ def decode_timestamp_ms(snowflake_id: int, epoch_ms: int = EPOCH_MS_DEFAULT) -> generated. """ # TODO: реализуйте функцию - return 0 + time_res = snowflake_id >> TIMESTAMP_SHIFT + return time_res + epoch_ms def decode_node_id(snowflake_id: int) -> int: @@ -65,7 +68,8 @@ def decode_node_id(snowflake_id: int) -> int: ``[0, NODE_ID_MAX]``. """ # TODO: реализуйте функцию - return 0 + node_id = (snowflake_id >> SEQUENCE_ID_BITS) & NODE_ID_MAX + return node_id def decode_sequence_id(snowflake_id: int) -> int: @@ -79,7 +83,8 @@ def decode_sequence_id(snowflake_id: int) -> int: the range ``[0, SEQUENCE_ID_MAX]``. """ # TODO: реализуйте функцию - return 0 + sequence_id = snowflake_id & SEQUENCE_ID_MAX + return sequence_id def generate_snowflake_id( @@ -111,4 +116,17 @@ def generate_snowflake_id( cases an explanatory message is printed to stdout first. """ # TODO: реализуйте функцию - return 0 + if not (0 <= sequence_id <= SEQUENCE_ID_MAX): + print(f"sequence_id must be >= 0 and <= {SEQUENCE_ID_MAX}") + return None + if not (0 <= node_id <= NODE_ID_MAX): + print(f"node_id must be >= 0 and <= {NODE_ID_MAX}") + return None + timestamp = read_current_millis(epoch_ms) + if not (0 <= timestamp <= TIMESTAMP_MS_MAX): + print(f"timestamp must be >= 0 and <= {TIMESTAMP_MS_MAX}") + return None + node_res = node_id << NODE_ID_SHIFT + timestamp_res = timestamp << TIMESTAMP_SHIFT + result = timestamp_res | node_res | sequence_id + return result From 4580922e3ecf81ee40f574a12e5f5e8132a6ae50 Mon Sep 17 00:00:00 2001 From: alpen9 Date: Fri, 25 Sep 2026 21:26:35 +0300 Subject: [PATCH 02/11] Solve task 1 --- src/part1/snowflake.py | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/src/part1/snowflake.py b/src/part1/snowflake.py index 0a09b53b..4d08ab45 100644 --- a/src/part1/snowflake.py +++ b/src/part1/snowflake.py @@ -15,7 +15,7 @@ import time -from .constants import ( +from constants import ( EPOCH_MS_DEFAULT, NODE_ID_DEFAULT, NODE_ID_MAX, @@ -117,16 +117,17 @@ def generate_snowflake_id( """ # TODO: реализуйте функцию if not (0 <= sequence_id <= SEQUENCE_ID_MAX): - print(f"sequence_id must be >= 0 and <= {SEQUENCE_ID_MAX}") + print(f"sequence_id must be in >= 0 and <= {SEQUENCE_ID_MAX}") return None if not (0 <= node_id <= NODE_ID_MAX): - print(f"node_id must be >= 0 and <= {NODE_ID_MAX}") + print(f"node_id must be in >= 0 and <= {NODE_ID_MAX}") return None timestamp = read_current_millis(epoch_ms) if not (0 <= timestamp <= TIMESTAMP_MS_MAX): - print(f"timestamp must be >= 0 and <= {TIMESTAMP_MS_MAX}") + print(f"overflows") return None node_res = node_id << NODE_ID_SHIFT timestamp_res = timestamp << TIMESTAMP_SHIFT result = timestamp_res | node_res | sequence_id return result +print(generate_snowflake_id(0, -1)) From 3bd6743461216cccfcc5649ae03d3d9a6dcda941 Mon Sep 17 00:00:00 2001 From: alpen9 Date: Fri, 25 Sep 2026 21:30:46 +0300 Subject: [PATCH 03/11] Solve task 1 --- src/part1/snowflake.py | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/src/part1/snowflake.py b/src/part1/snowflake.py index 4d08ab45..b67739a5 100644 --- a/src/part1/snowflake.py +++ b/src/part1/snowflake.py @@ -15,7 +15,7 @@ import time -from constants import ( +from .constants import ( EPOCH_MS_DEFAULT, NODE_ID_DEFAULT, NODE_ID_MAX, @@ -116,12 +116,12 @@ def generate_snowflake_id( cases an explanatory message is printed to stdout first. """ # TODO: реализуйте функцию - if not (0 <= sequence_id <= SEQUENCE_ID_MAX): - print(f"sequence_id must be in >= 0 and <= {SEQUENCE_ID_MAX}") - return None if not (0 <= node_id <= NODE_ID_MAX): print(f"node_id must be in >= 0 and <= {NODE_ID_MAX}") return None + if not (0 <= sequence_id <= SEQUENCE_ID_MAX): + print(f"sequence_id must be in >= 0 and <= {SEQUENCE_ID_MAX}") + return None timestamp = read_current_millis(epoch_ms) if not (0 <= timestamp <= TIMESTAMP_MS_MAX): print(f"overflows") From 894a8049e42606a5c30b037c246815e17d162803 Mon Sep 17 00:00:00 2001 From: alpen9 Date: Fri, 25 Sep 2026 21:35:14 +0300 Subject: [PATCH 04/11] Solve task 1 --- src/part1/snowflake.py | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/src/part1/snowflake.py b/src/part1/snowflake.py index b67739a5..12da3cae 100644 --- a/src/part1/snowflake.py +++ b/src/part1/snowflake.py @@ -117,10 +117,10 @@ def generate_snowflake_id( """ # TODO: реализуйте функцию if not (0 <= node_id <= NODE_ID_MAX): - print(f"node_id must be in >= 0 and <= {NODE_ID_MAX}") + print(f"node_id must be [0, {NODE_ID_MAX}]") return None if not (0 <= sequence_id <= SEQUENCE_ID_MAX): - print(f"sequence_id must be in >= 0 and <= {SEQUENCE_ID_MAX}") + print(f"sequence_id must be [0, {SEQUENCE_ID_MAX}") return None timestamp = read_current_millis(epoch_ms) if not (0 <= timestamp <= TIMESTAMP_MS_MAX): From da1a28409c4f734333ad327eebcacdfac2e98748 Mon Sep 17 00:00:00 2001 From: alpen9 Date: Fri, 25 Sep 2026 21:39:04 +0300 Subject: [PATCH 05/11] Solve task 1 --- src/part1/snowflake.py | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/src/part1/snowflake.py b/src/part1/snowflake.py index 12da3cae..4a3d902e 100644 --- a/src/part1/snowflake.py +++ b/src/part1/snowflake.py @@ -117,10 +117,10 @@ def generate_snowflake_id( """ # TODO: реализуйте функцию if not (0 <= node_id <= NODE_ID_MAX): - print(f"node_id must be [0, {NODE_ID_MAX}]") + print(f"node_id must be in [0, {NODE_ID_MAX}]") return None if not (0 <= sequence_id <= SEQUENCE_ID_MAX): - print(f"sequence_id must be [0, {SEQUENCE_ID_MAX}") + print(f"sequence_id must be in [0, {SEQUENCE_ID_MAX}") return None timestamp = read_current_millis(epoch_ms) if not (0 <= timestamp <= TIMESTAMP_MS_MAX): @@ -130,4 +130,3 @@ def generate_snowflake_id( timestamp_res = timestamp << TIMESTAMP_SHIFT result = timestamp_res | node_res | sequence_id return result -print(generate_snowflake_id(0, -1)) From 9eb51cfdb614290d55135d34299fba51d39f3b95 Mon Sep 17 00:00:00 2001 From: alpen9 Date: Fri, 25 Sep 2026 21:40:01 +0300 Subject: [PATCH 06/11] Solve task 1 --- src/part1/snowflake.py | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/part1/snowflake.py b/src/part1/snowflake.py index 4a3d902e..35733c24 100644 --- a/src/part1/snowflake.py +++ b/src/part1/snowflake.py @@ -120,7 +120,7 @@ def generate_snowflake_id( print(f"node_id must be in [0, {NODE_ID_MAX}]") return None if not (0 <= sequence_id <= SEQUENCE_ID_MAX): - print(f"sequence_id must be in [0, {SEQUENCE_ID_MAX}") + print(f"sequence_id must be in [0, {SEQUENCE_ID_MAX}]") return None timestamp = read_current_millis(epoch_ms) if not (0 <= timestamp <= TIMESTAMP_MS_MAX): From ff147586fff55520d851141e1791d4e396b799b0 Mon Sep 17 00:00:00 2001 From: alpen9 Date: Fri, 25 Sep 2026 21:46:08 +0300 Subject: [PATCH 07/11] Solve task 1 --- src/part1/snowflake.py | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/src/part1/snowflake.py b/src/part1/snowflake.py index 35733c24..d1fbb88f 100644 --- a/src/part1/snowflake.py +++ b/src/part1/snowflake.py @@ -117,10 +117,10 @@ def generate_snowflake_id( """ # TODO: реализуйте функцию if not (0 <= node_id <= NODE_ID_MAX): - print(f"node_id must be in [0, {NODE_ID_MAX}]") + print(f"node_id must be in [0, {NODE_ID_MAX}], but you wrote {node_id}") return None if not (0 <= sequence_id <= SEQUENCE_ID_MAX): - print(f"sequence_id must be in [0, {SEQUENCE_ID_MAX}]") + print(f"sequence_id must be in [0, {SEQUENCE_ID_MAX}], but you wrote {sequence_id}") return None timestamp = read_current_millis(epoch_ms) if not (0 <= timestamp <= TIMESTAMP_MS_MAX): From c6aa5e575b9cbc44f98a4d638573b412c0fe2e40 Mon Sep 17 00:00:00 2001 From: alpen9 Date: Fri, 25 Sep 2026 21:47:05 +0300 Subject: [PATCH 08/11] Solve task 1 --- src/part1/snowflake.py | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/part1/snowflake.py b/src/part1/snowflake.py index d1fbb88f..a07bdd77 100644 --- a/src/part1/snowflake.py +++ b/src/part1/snowflake.py @@ -124,7 +124,7 @@ def generate_snowflake_id( return None timestamp = read_current_millis(epoch_ms) if not (0 <= timestamp <= TIMESTAMP_MS_MAX): - print(f"overflows") + print("overflows") return None node_res = node_id << NODE_ID_SHIFT timestamp_res = timestamp << TIMESTAMP_SHIFT From 4d222137bebea2174b72c84ffa817932a6b971d8 Mon Sep 17 00:00:00 2001 From: alpen9 Date: Fri, 25 Sep 2026 23:11:11 +0300 Subject: [PATCH 09/11] Solve task 1 --- src/part1/snowflake.py | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/src/part1/snowflake.py b/src/part1/snowflake.py index a07bdd77..0777a5ee 100644 --- a/src/part1/snowflake.py +++ b/src/part1/snowflake.py @@ -117,10 +117,14 @@ def generate_snowflake_id( """ # TODO: реализуйте функцию if not (0 <= node_id <= NODE_ID_MAX): - print(f"node_id must be in [0, {NODE_ID_MAX}], but you wrote {node_id}") + print( + f"node_id must be in [0, {NODE_ID_MAX}], but you wrote {node_id}" + ) return None if not (0 <= sequence_id <= SEQUENCE_ID_MAX): - print(f"sequence_id must be in [0, {SEQUENCE_ID_MAX}], but you wrote {sequence_id}") + print( + f"sequence_id must be in [0, {SEQUENCE_ID_MAX}], but you wrote {sequence_id}" + ) return None timestamp = read_current_millis(epoch_ms) if not (0 <= timestamp <= TIMESTAMP_MS_MAX): From 18cdca82d44f83e0bfec9252f84e7944e37dd4b2 Mon Sep 17 00:00:00 2001 From: alpen9 Date: Fri, 25 Sep 2026 23:20:51 +0300 Subject: [PATCH 10/11] Solve task 1 --- src/part1/snowflake.py | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/src/part1/snowflake.py b/src/part1/snowflake.py index 0777a5ee..56204d22 100644 --- a/src/part1/snowflake.py +++ b/src/part1/snowflake.py @@ -117,14 +117,12 @@ def generate_snowflake_id( """ # TODO: реализуйте функцию if not (0 <= node_id <= NODE_ID_MAX): - print( - f"node_id must be in [0, {NODE_ID_MAX}], but you wrote {node_id}" - ) + print(f"node_id must be in [0, {NODE_ID_MAX}], but you wrote {node_id}") return None if not (0 <= sequence_id <= SEQUENCE_ID_MAX): print( f"sequence_id must be in [0, {SEQUENCE_ID_MAX}], but you wrote {sequence_id}" - ) + ) return None timestamp = read_current_millis(epoch_ms) if not (0 <= timestamp <= TIMESTAMP_MS_MAX): From bfaa64b7c00aa42c2b8d6c500631f19b95ed92ea Mon Sep 17 00:00:00 2001 From: alpen9 Date: Fri, 2 Oct 2026 20:05:33 +0300 Subject: [PATCH 11/11] Solve task 2 --- src/part2/cart.py | 47 ++++++++++++++++++++++++++++++++++++++++---- src/part2/crud.py | 41 ++++++++++++++++++++++++++++++++------ src/part2/storage.py | 8 ++++---- src/part2/utils.py | 6 +++--- 4 files changed, 85 insertions(+), 17 deletions(-) diff --git a/src/part2/cart.py b/src/part2/cart.py index 063f9aea..2ec984eb 100644 --- a/src/part2/cart.py +++ b/src/part2/cart.py @@ -24,8 +24,13 @@ # 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 line[LINE_PRODUCT_ID_INDEX] == product_id: + return line + return None def add_to_cart( storage: list[Product], @@ -54,8 +59,21 @@ def add_to_cart( 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: + if product[QUANTITY_INDEX] < quantity: + print(f"not enough stock for product {product_id}: {product[QUANTITY_INDEX]} available, {quantity} requested") + return None + product = update_product(storage, product_id, (product[NAME_INDEX], product[PRICE_INDEX], product[QUANTITY_INDEX] - quantity)) + for line in cart: + if line[LINE_PRODUCT_ID_INDEX] == product_id: + new_line = (product_id, line[LINE_QUANTITY_INDEX] + quantity) + cart[cart.index(line)] = new_line + return new_line + new_line =(product_id, quantity) + cart.append(new_line) + return new_line + return None def remove_from_cart( storage: list[Product], @@ -86,4 +104,25 @@ def remove_from_cart( 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) " + f"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 + if new_quantity == 0: + cart.remove(line) + return (product_id, 0) + new_line = (product_id, new_quantity) + cart[cart.index(line)] = new_line + return new_line \ No newline at end of file diff --git a/src/part2/crud.py b/src/part2/crud.py index d026cbcb..20da24e9 100644 --- a/src/part2/crud.py +++ b/src/part2/crud.py @@ -35,8 +35,12 @@ def generate_product_id(storage: list[Product]) -> int: empty. """ # TODO: реализуйте функцию - return 0 - + if not storage: + return PRODUCT_ID_MIN + max_id = 0 + for product in storage: + max_id = max(max_id, product[PRODUCT_ID_INDEX]) + return max_id + 1 def create_product( storage: list[Product], fields: tuple[str, Decimal, int] @@ -57,7 +61,15 @@ def create_product( 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) + normalized_price = normalize_price(price) + storage.append((product_id, name, normalized_price, quantity)) + return product_id def read_product(storage: list[Product], product_id: int) -> Product | None: @@ -73,7 +85,11 @@ def read_product(storage: list[Product], product_id: int) -> Product | None: 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( @@ -100,7 +116,15 @@ def update_product( left unchanged and a message is printed). """ # TODO: реализуйте функцию - return (0, "", Decimal(0), 0) + name, price, quantity = fields + price = normalize_price(price) + for product in storage: + if product[PRODUCT_ID_INDEX] == product_id: + updated_product = (product_id, name, price, quantity) + storage[storage.index(product)] = 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: @@ -117,4 +141,9 @@ def delete_product(storage: list[Product], product_id: int) -> int | None: a message is printed). """ # TODO: реализуйте функцию - return 0 + for product in storage: + if product[PRODUCT_ID_INDEX] == product_id: + storage.remove(product) + 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..35821c5f 100644 --- a/src/part2/storage.py +++ b/src/part2/storage.py @@ -26,9 +26,9 @@ # 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..f4cdc43b 100644 --- a/src/part2/utils.py +++ b/src/part2/utils.py @@ -11,8 +11,8 @@ # 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: @@ -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)