2. Цельт Валентин Эдуардович. 612

.gitignore

@@ -11,3 +11,6 @@ __pycache__/
 
 # Claude
 .claude
+
+# local repo dumps
+repo_dump*.txt

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] = (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 = SEQUENCE_ID_BITS
+TIMESTAMP_SHIFT = NODE_ID_SHIFT + NODE_ID_BITS

src/part1/snowflake.py

@@ -4,23 +4,25 @@
 coordination between nodes. Each identifier packs the milliseconds elapsed
 since a custom epoch, a node identifier and a per-millisecond sequence counter
 into a single 63-bit positive integer (see ``constants`` for the layout).
-
+gfvhjn
 The public entry point is :func:`generate_snowflake_id`. It is stateless: the
-caller passes the sequence counter on every call and is responsible for
+caller passes the sequence counter on every call and is responsible forderftgvhj
 advancing it within a millisecond and resetting it when the clock ticks over.
 
 Each packed field can be read back on its own with :func:`decode_timestamp_ms`,
 :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_MAX,
     TIMESTAMP_MS_MAX,
+    TIMESTAMP_SHIFT,
 )
 
 
@@ -35,7 +37,8 @@ def read_current_millis(epoch_ms: int) -> int:
         negative if ``epoch_ms`` lies in the future.
     """
     # TODO: реализуйте функцию
-    return 0
+    current_ms = int(time.time() * 1000)
+    return current_ms - epoch_ms
 
 
 def decode_timestamp_ms(snowflake_id: int, epoch_ms: int = EPOCH_MS_DEFAULT) -> int:
@@ -50,8 +53,8 @@ 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
+    timestamp = snowflake_id >> TIMESTAMP_SHIFT
+    return timestamp + epoch_ms
 
 
 def decode_node_id(snowflake_id: int) -> int:
@@ -64,8 +67,7 @@ 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 +80,7 @@ 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 +111,16 @@ 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
+
+    current_ms = read_current_millis(epoch_ms)
+    if current_ms > TIMESTAMP_MS_MAX:
+        print("timestamp overflows")
+        return None
+    return (current_ms << TIMESTAMP_SHIFT) | (node_id << NODE_ID_SHIFT) | sequence_id

src/part2/cart.py

@@ -11,7 +11,7 @@
 
 from typing import Final
 
-from .crud import read_product, update_product  # noqa: F401
+from .crud import read_product, update_product # noqa: F401
 from .storage import (  # noqa: F401
     NAME_INDEX,
     PRICE_INDEX,
@@ -22,11 +22,16 @@
 
 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) -> int | None:
+    for cart_ in cart:
+        if cart_[LINE_PRODUCT_ID_INDEX] == product_id:
+            return cart.index(cart_)
+    return None
+
 def add_to_cart(
     storage: list[Product],
     cart: list[CartLine],
@@ -53,9 +58,26 @@ 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_person = read_product(storage, product_id)
+    if not product_person:
+        return None 
+    storage_quantity = product_person[QUANTITY_INDEX]
+    if storage_quantity < quantity:
+        print(f"not enough stock for product {product_id} : {product_person[QUANTITY_INDEX]} available, {quantity} requested")
+        return None
+
+    fields_ = (product_person[NAME_INDEX], product_person[PRICE_INDEX], product_person[QUANTITY_INDEX] - quantity) 
+    update_product(storage, product_id, fields_)  
+
+    line_index = find_cart_line(cart, product_id)
+    if line_index is None:
+        cartLine = (product_id, quantity)
+        cart.append(cartLine)
+        return cartLine
+    old_quantity = cart[line_index][LINE_QUANTITY_INDEX]
+    cartLine = (product_id, old_quantity + quantity)
+    cart[line_index] = cartLine
+    return cartLine
 
 def remove_from_cart(
     storage: list[Product],
@@ -85,5 +107,27 @@ 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_index = find_cart_line(cart, product_id)
+    if line_index is None:
+        print(f"product {product_id} is not in the cart")
+        return None 
+
+    cart_quantity = cart[line_index][LINE_QUANTITY_INDEX]
+    if cart_quantity < quantity:
+        print(f"cart holds only {cart_quantity} unit(s) of product")
+        print(f"{product_id}, cannot remove {quantity}")
+        return None
+
+    product_person = read_product(storage, product_id)
+    if not product_person:
+        return None
+
+    fields_ = (product_person[NAME_INDEX],product_person[PRICE_INDEX],product_person[QUANTITY_INDEX] + quantity)
+    update_product(storage, product_id, fields_)
+
+    new_cart_quantity = cart_quantity - quantity
+    if new_cart_quantity == 0:
+        del cart[line_index]
+    else:
+        cart[line_index] = (product_id, new_cart_quantity)
+    return (product_id, new_cart_quantity)

src/part2/crud.py

@@ -34,9 +34,9 @@ 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(
     storage: list[Product], fields: tuple[str, Decimal, int]
@@ -56,8 +56,16 @@ 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
+    product_id = generate_product_id(storage)
+    product_price = normalize_price(price)
+    new_product = (product_id, name, product_price, quantity)
+    storage.append(new_product)
+    return  product_id
 
 
 def read_product(storage: list[Product], product_id: int) -> Product | None:
@@ -72,8 +80,12 @@ 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[PRODUCT_ID_INDEX] == product_id:
+            return product
+
+    print (f"no product with id {product_id}")
+    return None
 
 
 def update_product(
@@ -99,8 +111,16 @@ 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
+
+    for product in storage:
+        if product[PRODUCT_ID_INDEX] == product_id:
+            new_product = (product_id, name, normalize_price(price), quantity)
+            storage[storage.index(product)] = new_product  
+            return new_product
+
+    print (f"no product with id {product_id}")
+    return None
 
 
 def delete_product(storage: list[Product], product_id: int) -> int | None:
@@ -116,5 +136,10 @@ 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 product_index in storage:
+        if product_index[PRODUCT_ID_INDEX] == product_id:
+            storage.remove(product_index)
+            return product_id
+
+    print (f"no product with id {product_id}")
+    return None

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

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 +26,5 @@ 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)