From 31764411b9a4481d5de371ff9878f9d3e8cb8fc2 Mon Sep 17 00:00:00 2001
From: Kiriil <kitkat28598@gmail.com>
Date: Tue, 22 Sep 2026 18:33:22 +0300
Subject: [PATCH 01/12] Update constants.py

---
 src/part1/constants.py | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/part1/constants.py b/src/part1/constants.py
index 9abfbba2..8d49454a 100644
--- a/src/part1/constants.py
+++ b/src/part1/constants.py
@@ -19,20 +19,20 @@
 # 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**41-1
+NODE_ID_MAX: Final[int] = 2**10-1
+SEQUENCE_ID_MAX: Final[int] = 2**12-1
 
 # Здесь можно добавить собственные вспомогательные константы
 # (например, сдвиги полей при сборке идентификатора).

From 259056ff644225d62a69d3bd7263c46e0d51be70 Mon Sep 17 00:00:00 2001
From: Kiriil <kitkat28598@gmail.com>
Date: Tue, 22 Sep 2026 18:49:01 +0300
Subject: [PATCH 02/12] Update snowflake.py

---
 src/part1/snowflake.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/part1/snowflake.py b/src/part1/snowflake.py
index d3abf050..88c26f9b 100644
--- a/src/part1/snowflake.py
+++ b/src/part1/snowflake.py
@@ -35,7 +35,8 @@ def read_current_millis(epoch_ms: int) -> int:
         negative if ``epoch_ms`` lies in the future.
     """
     # TODO: реализуйте функцию
-    return 0
+    a = (time.time_ns() // 1000000) - epoch_ms
+    return a
 
 
 def decode_timestamp_ms(snowflake_id: int, epoch_ms: int = EPOCH_MS_DEFAULT) -> int:

From bf69af282104c28c3866c4ae052a07a29b68f8ca Mon Sep 17 00:00:00 2001
From: Kiriil <kitkat28598@gmail.com>
Date: Tue, 22 Sep 2026 23:42:50 +0300
Subject: [PATCH 03/12] Update snowflake.py

---
 src/part1/snowflake.py | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/src/part1/snowflake.py b/src/part1/snowflake.py
index 88c26f9b..46efd267 100644
--- a/src/part1/snowflake.py
+++ b/src/part1/snowflake.py
@@ -21,6 +21,8 @@
     NODE_ID_MAX,
     SEQUENCE_ID_MAX,
     TIMESTAMP_MS_MAX,
+    NODE_ID_BITS,
+    SEQUENCE_ID_BITS,
 )
 
 
@@ -52,7 +54,8 @@ def decode_timestamp_ms(snowflake_id: int, epoch_ms: int = EPOCH_MS_DEFAULT) ->
         generated.
     """
     # TODO: реализуйте функцию
-    return 0
+    epoch_time = snowflake_id >> (SEQUENCE_ID_BITS+NODE_ID_BITS)
+    return epoch_time + epoch_ms
 
 
 def decode_node_id(snowflake_id: int) -> int:
@@ -66,7 +69,8 @@ def decode_node_id(snowflake_id: int) -> int:
         ``[0, NODE_ID_MAX]``.
     """
     # TODO: реализуйте функцию
-    return 0
+    node_num = (snowflake_id >> SEQUENCE_ID_BITS) & NODE_ID_MAX
+    return node_num
 
 
 def decode_sequence_id(snowflake_id: int) -> int:
@@ -80,7 +84,8 @@ def decode_sequence_id(snowflake_id: int) -> int:
         the range ``[0, SEQUENCE_ID_MAX]``.
     """
     # TODO: реализуйте функцию
-    return 0
+    seq_id = snowflake_id & SEQUENCE_ID_MAX
+    return seq_id
 
 
 def generate_snowflake_id(
@@ -112,4 +117,10 @@ def generate_snowflake_id(
         cases an explanatory message is printed to stdout first.
     """
     # TODO: реализуйте функцию
+    if 0<=node_id<=NODE_ID_MAX:
+        return "node_id must be in [0, NODE_ID_MAX]"
+    else if 0 <= sequence_id <= SEQUENCE_ID_MAX:
+        return "sequence_id must be in [0, SEQUENCE_ID_MAX]"
+    else:
+        
     return 0

From 316aee5036e7824ac620e0ed4bee8c2833f34486 Mon Sep 17 00:00:00 2001
From: Kirill <kitkat28598@gmail.com>
Date: Wed, 23 Sep 2026 00:18:53 +0300
Subject: [PATCH 04/12] Finished homework

---
 src/part1/snowflake.py | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/src/part1/snowflake.py b/src/part1/snowflake.py
index 46efd267..6888cc4c 100644
--- a/src/part1/snowflake.py
+++ b/src/part1/snowflake.py
@@ -117,10 +117,15 @@ def generate_snowflake_id(
         cases an explanatory message is printed to stdout first.
     """
     # TODO: реализуйте функцию
-    if 0<=node_id<=NODE_ID_MAX:
-        return "node_id must be in [0, NODE_ID_MAX]"
-    else if 0 <= sequence_id <= SEQUENCE_ID_MAX:
-        return "sequence_id must be in [0, SEQUENCE_ID_MAX]"
+    a = (time.time_ns() // 1000000) - epoch_ms
+    if not (0<=node_id<=NODE_ID_MAX):
+        print(f"node_id must be in [0, {NODE_ID_MAX}], got {node_id}")
+        return None
+    elif not(0 <= sequence_id <= SEQUENCE_ID_MAX):
+        print(f"sequence_id must be in [0, {SEQUENCE_ID_MAX}], got {sequence_id}")
+        return None
+    if a > TIMESTAMP_MS_MAX:
+        print("overflows")
+        return None
     else:
-        
-    return 0
+        return (a << 22) | (node_id << 12) | sequence_id
\ No newline at end of file

From da22fa8bc7f17f1ff645af961f74a6931f68d333 Mon Sep 17 00:00:00 2001
From: Kirill <kitkat28598@gmail.com>
Date: Wed, 23 Sep 2026 00:47:35 +0300
Subject: [PATCH 05/12] Finished homework

---
 src/part1/constants.py |  6 +++---
 src/part1/snowflake.py | 19 +++++++++++--------
 2 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/src/part1/constants.py b/src/part1/constants.py
index 8d49454a..22c27cee 100644
--- a/src/part1/constants.py
+++ b/src/part1/constants.py
@@ -30,9 +30,9 @@
 SEQUENCE_ID_BITS: Final[int] = 12
 
 # Largest value each field can hold.
-TIMESTAMP_MS_MAX: Final[int] = 2**41-1
-NODE_ID_MAX: Final[int] = 2**10-1
-SEQUENCE_ID_MAX: Final[int] = 2**12-1
+TIMESTAMP_MS_MAX: Final[int] = 2**41 - 1
+NODE_ID_MAX: Final[int] = 2**10 - 1
+SEQUENCE_ID_MAX: Final[int] = 2**12 - 1
 
 # Здесь можно добавить собственные вспомогательные константы
 # (например, сдвиги полей при сборке идентификатора).
diff --git a/src/part1/snowflake.py b/src/part1/snowflake.py
index 6888cc4c..145fa740 100644
--- a/src/part1/snowflake.py
+++ b/src/part1/snowflake.py
@@ -13,16 +13,19 @@
 :func:`decode_node_id` and :func:`decode_sequence_id`.
 """
 
-import time  # noqa: F401
+import time
 
-from .constants import (  # noqa: F401
+from .constants import (
+    # Epoch
     EPOCH_MS_DEFAULT,
+    # Node ID
+    NODE_ID_BITS,
     NODE_ID_DEFAULT,
     NODE_ID_MAX,
+    # Sequence ID
+    SEQUENCE_ID_BITS,
     SEQUENCE_ID_MAX,
     TIMESTAMP_MS_MAX,
-    NODE_ID_BITS,
-    SEQUENCE_ID_BITS,
 )
 
 
@@ -54,7 +57,7 @@ def decode_timestamp_ms(snowflake_id: int, epoch_ms: int = EPOCH_MS_DEFAULT) ->
         generated.
     """
     # TODO: реализуйте функцию
-    epoch_time = snowflake_id >> (SEQUENCE_ID_BITS+NODE_ID_BITS)
+    epoch_time = snowflake_id >> (SEQUENCE_ID_BITS + NODE_ID_BITS)
     return epoch_time + epoch_ms
 
 
@@ -118,14 +121,14 @@ def generate_snowflake_id(
     """
     # TODO: реализуйте функцию
     a = (time.time_ns() // 1000000) - epoch_ms
-    if not (0<=node_id<=NODE_ID_MAX):
+    if not (0 <= node_id <= NODE_ID_MAX):
         print(f"node_id must be in [0, {NODE_ID_MAX}], got {node_id}")
         return None
-    elif not(0 <= sequence_id <= SEQUENCE_ID_MAX):
+    elif not (0 <= sequence_id <= SEQUENCE_ID_MAX):
         print(f"sequence_id must be in [0, {SEQUENCE_ID_MAX}], got {sequence_id}")
         return None
     if a > TIMESTAMP_MS_MAX:
         print("overflows")
         return None
     else:
-        return (a << 22) | (node_id << 12) | sequence_id
\ No newline at end of file
+        return (a << 22) | (node_id << 12) | sequence_id

From 8a228860b6df217964f9ffd706bf182ae9542c17 Mon Sep 17 00:00:00 2001
From: Kirill <kitkat28598@gmail.com>
Date: Wed, 23 Sep 2026 00:58:05 +0300
Subject: [PATCH 06/12] Finished homework

---
 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 145fa740..c137f122 100644
--- a/src/part1/snowflake.py
+++ b/src/part1/snowflake.py
@@ -120,15 +120,15 @@ def generate_snowflake_id(
         cases an explanatory message is printed to stdout first.
     """
     # TODO: реализуйте функцию
-    a = (time.time_ns() // 1000000) - epoch_ms
     if not (0 <= node_id <= NODE_ID_MAX):
         print(f"node_id must be in [0, {NODE_ID_MAX}], got {node_id}")
         return None
     elif not (0 <= sequence_id <= SEQUENCE_ID_MAX):
         print(f"sequence_id must be in [0, {SEQUENCE_ID_MAX}], got {sequence_id}")
         return None
+    a = (time.time_ns() // 1000000) - epoch_ms
     if a > TIMESTAMP_MS_MAX:
         print("overflows")
         return None
     else:
-        return (a << 22) | (node_id << 12) | sequence_id
+        return (a << NODE_ID_BITS + SEQUENCE_ID_BITS) | (node_id << SEQUENCE_ID_BITS) | sequence_id

From 268bc4ffd5663eab2532ffb1fae75a9548cb5ad0 Mon Sep 17 00:00:00 2001
From: Kirill <kitkat28598@gmail.com>
Date: Thu, 24 Sep 2026 01:03:12 +0300
Subject: [PATCH 07/12] Finished homework

---
 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 c137f122..f34cff25 100644
--- a/src/part1/snowflake.py
+++ b/src/part1/snowflake.py
@@ -131,4 +131,4 @@ def generate_snowflake_id(
         print("overflows")
         return None
     else:
-        return (a << NODE_ID_BITS + SEQUENCE_ID_BITS) | (node_id << SEQUENCE_ID_BITS) | sequence_id
+        return (a << (NODE_ID_BITS + SEQUENCE_ID_BITS)) | (node_id << SEQUENCE_ID_BITS) | sequence_id

From c5e0f2f362a5f73fd1b85a999f818909eff4e851 Mon Sep 17 00:00:00 2001
From: Kirill <kitkat28598@gmail.com>
Date: Thu, 24 Sep 2026 01:07:09 +0300
Subject: [PATCH 08/12] Finished homework

---
 src/part1/snowflake.py | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/part1/snowflake.py b/src/part1/snowflake.py
index f34cff25..8c015a63 100644
--- a/src/part1/snowflake.py
+++ b/src/part1/snowflake.py
@@ -131,4 +131,8 @@ def generate_snowflake_id(
         print("overflows")
         return None
     else:
-        return (a << (NODE_ID_BITS + SEQUENCE_ID_BITS)) | (node_id << SEQUENCE_ID_BITS) | sequence_id
+        return (
+            (a << (NODE_ID_BITS + SEQUENCE_ID_BITS))
+            | (node_id << SEQUENCE_ID_BITS)
+            | sequence_id
+        )

From 89df45e05367308f3f4985740c2abf21ce8fd34f Mon Sep 17 00:00:00 2001
From: Kirill <kitkat28598@gmail.com>
Date: Mon, 28 Sep 2026 23:53:36 +0300
Subject: [PATCH 09/12] process of homework

---
 src/part2/crud.py    | 20 +++++++++++++++++---
 src/part2/storage.py |  8 ++++----
 src/part2/utils.py   |  6 +++---
 3 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/src/part2/crud.py b/src/part2/crud.py
index d026cbcb..88e64581 100644
--- a/src/part2/crud.py
+++ b/src/part2/crud.py
@@ -35,7 +35,9 @@ def generate_product_id(storage: list[Product]) -> int:
         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(
@@ -57,8 +59,16 @@ def create_product(
         name is printed.
     """
     # TODO: реализуйте функцию
-    return 0
+    
+    name, price, quan = fields
+    n_id = generate_product_id(storage)
 
+    if any(product[NAME_INDEX] == name for product in storage):
+        print(f"product name '{name}' is already taken")
+        return None
+
+    storage.append((n_id, name, normalize_price(price), quan))
+    return n_id
 
 def read_product(storage: list[Product], product_id: int) -> Product | None:
     """Return the product stored under ``product_id``.
@@ -73,7 +83,11 @@ 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(
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)

From bdc5c1b7f08376896b8ffd8f3a687d43be3f031a Mon Sep 17 00:00:00 2001
From: Kirill <kitkat28598@gmail.com>
Date: Wed, 30 Sep 2026 16:16:25 +0300
Subject: [PATCH 10/12] finished crud

---
 src/part2/crud.py | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/src/part2/crud.py b/src/part2/crud.py
index 88e64581..90f5a8dc 100644
--- a/src/part2/crud.py
+++ b/src/part2/crud.py
@@ -37,7 +37,7 @@ def generate_product_id(storage: list[Product]) -> int:
     # TODO: реализуйте функцию
     if not storage:
         return PRODUCT_ID_MIN
-    return max(product(PRODUCT_ID_INDEX) for product in storage) + 1
+    return max(product[PRODUCT_ID_INDEX] for product in storage) + 1
 
 
 def create_product(
@@ -114,7 +114,14 @@ def update_product(
         left unchanged and a message is printed).
     """
     # TODO: реализуйте функцию
-    return (0, "", Decimal(0), 0)
+    name, price, qual = fields
+    for i, product in enumerate(storage):
+        if product[PRODUCT_ID_INDEX] == product_id:
+            update = (product_id, name, normalize_price(price), qual)
+            storage[i] = update
+            return update
+    print(f"no product with id {product_id}")
+    return None
 
 
 def delete_product(storage: list[Product], product_id: int) -> int | None:
@@ -131,4 +138,9 @@ 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
\ No newline at end of file

From 059081ec5679a3e13c2253655e3ec5c54f055c7b Mon Sep 17 00:00:00 2001
From: Kirill <kitkat28598@gmail.com>
Date: Fri, 2 Oct 2026 17:55:56 +0300
Subject: [PATCH 11/12] Finished homework

---
 src/part2/cart.py  | 75 ++++++++++++++++++++++++++++++++++++++++++----
 src/part2/crud.py  |  9 +++---
 src/part2/utils.py |  2 +-
 3 files changed, 76 insertions(+), 10 deletions(-)

diff --git a/src/part2/cart.py b/src/part2/cart.py
index 063f9aea..0fac6e6b 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,
@@ -24,7 +24,17 @@
 
 # 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 cart_line in cart:
+        if cart_line[LINE_PRODUCT_ID_INDEX] == product_id:
+            return cart_line
+    return None
 
 
 def add_to_cart(
@@ -54,7 +64,33 @@ 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 is None:
+        return None
+    stock = product[QUANTITY_INDEX]
+    if stock < quantity:
+        print(
+            f"not enough stock for product {product_id}: {stock} available, {quantity} requested"
+        )
+        return None
+
+    update_product(
+        storage,
+        product_id,
+        (product[NAME_INDEX], product[PRICE_INDEX], stock - quantity),
+    )
+    cart_line = find_cart_line(cart, product_id)
+
+    if cart_line is not None:
+        new_cart_line = (product_id, quantity + cart_line[LINE_QUANTITY_INDEX])
+        for i in range(len(cart)):
+            if cart[i][LINE_PRODUCT_ID_INDEX] == product_id:
+                cart[i] = new_cart_line
+        return new_cart_line
+    else:
+        new_cart_line = (product_id, quantity)
+        cart.append(new_cart_line)
+        return new_cart_line
 
 
 def remove_from_cart(
@@ -86,4 +122,33 @@ def remove_from_cart(
         line for the product or holds too few units.
     """
     # TODO: реализуйте функцию
-    return (0, 0)
+    cart_line = find_cart_line(cart, product_id)
+
+    if cart_line is None:
+        print(f"product {product_id} is not in the cart")
+        return None
+    stock_in_cart = cart_line[LINE_QUANTITY_INDEX]
+    if stock_in_cart < quantity:
+        print(
+            f"cart holds only {stock_in_cart} unit(s) of product {product_id}, cannot remove {quantity}"
+        )
+        return None
+    product = read_product(storage, product_id)
+    if product is None:
+        return None
+    stock_in_product = product[QUANTITY_INDEX]
+    update_product(
+        storage,
+        product_id,
+        (product[NAME_INDEX], product[PRICE_INDEX], stock_in_product + quantity),
+    )
+
+    new_cart_line = (product_id, stock_in_cart - quantity)
+    index_cart_line = cart.index(cart_line)
+
+    if (stock_in_cart - quantity) != 0:
+        cart[index_cart_line] = new_cart_line
+    else:
+        cart.pop(index_cart_line)
+
+    return new_cart_line
diff --git a/src/part2/crud.py b/src/part2/crud.py
index 90f5a8dc..38544578 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:
@@ -59,7 +59,7 @@ def create_product(
         name is printed.
     """
     # TODO: реализуйте функцию
-    
+
     name, price, quan = fields
     n_id = generate_product_id(storage)
 
@@ -70,6 +70,7 @@ def create_product(
     storage.append((n_id, name, normalize_price(price), quan))
     return n_id
 
+
 def read_product(storage: list[Product], product_id: int) -> Product | None:
     """Return the product stored under ``product_id``.
 
@@ -143,4 +144,4 @@ def delete_product(storage: list[Product], product_id: int) -> int | None:
             storage.remove(product)
             return product_id
     print(f"no product with id {product_id}")
-    return None
\ No newline at end of file
+    return None
diff --git a/src/part2/utils.py b/src/part2/utils.py
index f4cdc43b..26a20798 100644
--- a/src/part2/utils.py
+++ b/src/part2/utils.py
@@ -6,7 +6,7 @@
 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
 
 

From a37f462d724cbee18fa7388e7c165b1795d06f64 Mon Sep 17 00:00:00 2001
From: Kirill <kitkat28598@gmail.com>
Date: Fri, 9 Oct 2026 15:40:21 +0300
Subject: [PATCH 12/12] finished hometask

---
 src/part3/crud.py      | 108 ++++++++++++++++++++++++++++-------------
 src/part3/run_admin.py |  68 +++++++++++++++++++++++---
 src/part3/storage.py   |   8 +--
 src/part3/utils.py     |  58 +++++++++++++++++++---
 4 files changed, 190 insertions(+), 52 deletions(-)

diff --git a/src/part3/crud.py b/src/part3/crud.py
index 68811d7e..2472e2ef 100644
--- a/src/part3/crud.py
+++ b/src/part3/crud.py
@@ -1,32 +1,26 @@
 """Create/read/update/delete operations over the in-memory product store.
 
 Every operation takes the store -- a list of
-:data:`~src.part3.storage.Product` tuples -- as its first argument and
+:data:`~src.part2.storage.Product` tuples -- as its first argument and
 works on it in place. The failure path never raises: the operation prints
 an explanatory message to stdout and returns ``None``.
 
 The identifier of a new product is derived from the store itself
 (:func:`generate_product_id`): one past the greatest identifier in use, or
-:data:`~src.part3.storage.PRODUCT_ID_MIN` when the store is empty.
-
-Every product name that reaches the store is passed through
-:func:`~src.part3.utils.normalize_product_name` first. A name that
-normalises to an empty string is rejected -- the operation prints a
-message and changes nothing. Names are also kept unique --
-:func:`create_product` refuses a normalised name that is already taken,
-and :func:`update_product` refuses one that is already taken by another
-product.
+:data:`~src.part2.storage.PRODUCT_ID_MIN` when the store is empty.
+Product names are kept unique -- :func:`create_product` refuses a name that
+is already taken.
 """
 
 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, normalize_product_name  # noqa: F401
+from .utils import normalize_price, normalize_product_name
 
 
 def generate_product_id(storage: list[Product]) -> int:
@@ -37,11 +31,13 @@ def generate_product_id(storage: list[Product]) -> int:
 
     Returns:
         One past the greatest identifier currently held in ``storage``, or
-        :data:`~src.part3.storage.PRODUCT_ID_MIN` when ``storage`` is
+        :data:`~src.part2.storage.PRODUCT_ID_MIN` when ``storage`` is
         empty.
     """
-    # TODO: реализуйте функцию (используйте своё решение части 2)
-    return 0
+    # TODO: реализуйте функцию
+    if not storage:
+        return PRODUCT_ID_MIN
+    return max(product[PRODUCT_ID_INDEX] for product in storage) + 1
 
 
 def create_product(
@@ -53,19 +49,31 @@ def create_product(
         storage: The product store to append to; modified in place on
             success.
         fields: A ``(name, price, quantity)`` tuple describing the product.
-            ``name`` is normalised (surrounding whitespace stripped,
-            lower-cased) before it is stored or compared. ``price`` is a
-            :class:`~decimal.Decimal` amount and is rounded to the stored
-            money precision before it is saved.
+            ``price`` is a :class:`~decimal.Decimal` amount and is rounded
+            to the stored money precision before it is saved.
 
     Returns:
-        The identifier generated for the new product, or ``None`` when
-        ``name`` is blank once normalised or a product with the same
-        normalised name already exists. In the ``None`` case ``storage``
-        is left unchanged and an explanatory message is printed.
+        The identifier generated for the new product, or ``None`` when a
+        product with the same name already exists. In the ``None`` case
+        ``storage`` is left unchanged and a message naming the clashing
+        name is printed.
     """
     # TODO: реализуйте функцию
-    return 0
+
+    name1, price, quan = fields
+    name = normalize_product_name(name1)
+
+    if name == "":
+        print("product name must not be blank")
+        return None
+
+    if any(product[NAME_INDEX] == name for product in storage):
+        print(f"product name '{name}' is already taken")
+        return None
+
+    n_id = generate_product_id(storage)
+    storage.append((n_id, name, normalize_price(price), quan))
+    return n_id
 
 
 def read_product(storage: list[Product], product_id: int) -> Product | None:
@@ -80,8 +88,12 @@ 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 (используйте своё решение части 2)
-    return (0, "", Decimal(0), 0)
+    # TODO: реализуйте функцию
+    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(
@@ -104,14 +116,37 @@ def update_product(
 
     Returns:
         The updated ``(product_id, name, price, quantity)`` record, or
-        ``None`` when ``name`` is blank once normalised, no product
-        carries that identifier, or the normalised name is already taken
-        by another product. In every ``None`` case ``storage`` is left
-        unchanged and an explanatory message is printed. Renaming a
-        product to its own current name is allowed.
+        ``None`` when no product carries that identifier (``storage`` is
+        left unchanged and a message is printed).
     """
     # TODO: реализуйте функцию
-    return (0, "", Decimal(0), 0)
+    name1, price, qual = fields
+    name = normalize_product_name(name1)
+
+    if name == "":
+        print("product name must not be blank")
+        return None
+
+    index = None
+    for i, product in enumerate(storage):
+        if product[PRODUCT_ID_INDEX] == product_id:
+            index = i
+            break
+
+    if index is None:
+        print(f"no product with id {product_id}")
+        return None
+
+    if any(
+        product[NAME_INDEX] == name and product[PRODUCT_ID_INDEX] != product_id
+        for product in storage
+    ):
+        print(f"product name '{name}' is already taken")
+        return None
+
+    updated = (product_id, name, normalize_price(price), qual)
+    storage[index] = updated
+    return updated
 
 
 def delete_product(storage: list[Product], product_id: int) -> int | None:
@@ -127,5 +162,10 @@ 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 (используйте своё решение части 2)
-    return 0
+    # TODO: реализуйте функцию
+    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/part3/run_admin.py b/src/part3/run_admin.py
index c5feeb0b..626a678c 100644
--- a/src/part3/run_admin.py
+++ b/src/part3/run_admin.py
@@ -29,22 +29,33 @@
 it.
 """
 
-from decimal import Decimal, InvalidOperation  # noqa: F401
+from decimal import Decimal, InvalidOperation
 from typing import Final
 
-from .crud import (  # noqa: F401
+from .crud import (
     create_product,
     delete_product,
     read_product,
     update_product,
 )
 from .storage import Product
-from .utils import get_storage_str_representation  # noqa: F401
+from .utils import get_storage_str_representation
 
 
 # TODO: задайте приглашение и текст справки
-PROMPT: Final[str] = ""
-HELP_TEXT: Final[str] = ""
+PROMPT: Final[str] = "admin> "
+HELP_TEXT: Final[str] = """Available commands:
+  help                                       show this message
+  exit                                       leave the console
+  show                                       print the whole store as a table
+  create <name...> <price> <quantity>        add a product, print its new id
+  read <id>                                  print the product with that id
+  update <id> <name...> <price> <quantity>   overwrite that product's fields
+  delete <id>                                remove the product with that id
+
+For create and update the price and quantity are the last two words of the
+line; everything before them is the product name, so it may contain spaces
+(for example "Gibson SG Junior") and needs no quoting."""
 
 
 def show_help() -> None:
@@ -55,6 +66,7 @@ def show_help() -> None:
     note on how multi-word names are parsed.
     """
     # TODO: реализуйте функцию
+    print(HELP_TEXT)
 
 
 def print_result(result: object) -> None:
@@ -66,6 +78,8 @@ def print_result(result: object) -> None:
             printed in that case.
     """
     # TODO: реализуйте функцию
+    if result is not None:
+        print(result)
 
 
 def run_command(storage: list[Product], line: str) -> bool:
@@ -89,7 +103,49 @@ def run_command(storage: list[Product], line: str) -> bool:
             ``update`` does not parse as a decimal number.
     """
     # TODO: реализуйте функцию
-    return False
+
+    if line == "exit":
+        return False
+    if line == "help":
+        show_help()
+        return True
+    if line == "show":
+        print(get_storage_str_representation(storage))
+        return True
+
+    words = line.split()
+
+    if len(words) >= 4 and words[0] == "create":
+        name = " ".join(words[1:-2])
+        price = Decimal(words[-2])
+        quantity = int(words[-1])
+        result: object = create_product(storage, (name, price, quantity))
+        print_result(result)
+        return True
+
+    if len(words) == 2 and words[0] == "read":
+        product_id = int(words[1])
+        result = read_product(storage, product_id)
+        print_result(result)
+        return True
+
+    if len(words) >= 5 and words[0] == "update":
+        product_id = int(words[1])
+        name = " ".join(words[2:-2])
+        price = Decimal(words[-2])
+        quantity = int(words[-1])
+        result = update_product(storage, product_id, (name, price, quantity))
+        print_result(result)
+        return True
+
+    if len(words) == 2 and words[0] == "delete":
+        product_id = int(words[1])
+        result = delete_product(storage, product_id)
+        print_result(result)
+        return True
+
+    print(f"{line!s} is not a command")
+    return True
 
 
 def main() -> None:
diff --git a/src/part3/storage.py b/src/part3/storage.py
index c5e34be5..36e9af7f 100644
--- a/src/part3/storage.py
+++ b/src/part3/storage.py
@@ -27,9 +27,9 @@
 # TODO: задайте позиции полей внутри кортежа Product (используйте своё решение
 # части 2)
 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/part3/utils.py b/src/part3/utils.py
index 318ded0b..f2fbf0a3 100644
--- a/src/part3/utils.py
+++ b/src/part3/utils.py
@@ -18,7 +18,7 @@
   the longest value it holds in that particular call.
 """
 
-from decimal import ROUND_HALF_UP, Decimal  # noqa: F401
+from decimal import ROUND_HALF_UP, Decimal
 from typing import Final
 
 from .storage import Product
@@ -28,14 +28,14 @@
 # Quantisation step derived from PRICE_PRECISION, e.g. Decimal("0.01").
 # TODO: задайте число знаков после запятой и шаг квантования (используйте своё
 # решение части 2)
-PRICE_PRECISION: Final[int] = 0
-PRICE_STEP: Final = Decimal(0)
+PRICE_PRECISION: Final[int] = 2
+PRICE_STEP: Final = Decimal(1).scaleb(-PRICE_PRECISION)
 
 # Column headers of the table produced by get_storage_str_representation,
 # left to right. The width of each column is not fixed here -- it is
 # measured per call from the data (see the function).
 # TODO: задайте заголовки столбцов таблицы
-TABLE_HEADERS: Final[tuple[str, ...]] = ()
+TABLE_HEADERS: Final[tuple[str, ...]] = ("ID", "name", "price", "quantity")
 
 
 def normalize_price(price: Decimal) -> Decimal:
@@ -48,8 +48,8 @@ def normalize_price(price: Decimal) -> Decimal:
         ``price`` quantised to :data:`PRICE_PRECISION` fractional digits,
         with halves rounded up.
     """
-    # TODO: реализуйте функцию (используйте своё решение части 2)
-    return Decimal(0)
+    # TODO: реализуйте функцию
+    return price.quantize(PRICE_STEP, rounding=ROUND_HALF_UP)
 
 
 def normalize_product_name(name: str) -> str:
@@ -67,7 +67,7 @@ def normalize_product_name(name: str) -> str:
         whitespace.
     """
     # TODO: реализуйте функцию
-    return ""
+    return " ".join(name.split()).lower()
 
 
 # TODO: при необходимости добавьте свои вспомогательные функции
@@ -92,4 +92,46 @@ def get_storage_str_representation(storage: list[Product]) -> str:
         the header labels.
     """
     # TODO: реализуйте функцию
-    return ""
+    ids = []
+    names = []
+    prices = []
+    quantitys = []
+
+    for product in storage:
+        ids.append(str(product[0]))
+        names.append(product[1])
+        prices.append(str(product[2]))
+        quantitys.append(str(product[3]))
+
+    w_id = max(len(TABLE_HEADERS[0]), max((len(x) for x in ids), default=0))
+    w_name = max(len(TABLE_HEADERS[1]), max((len(x) for x in names), default=0))
+    w_pr = max(len(TABLE_HEADERS[2]), max((len(x) for x in prices), default=0))
+    w_qty = max(len(TABLE_HEADERS[3]), max((len(x) for x in quantitys), default=0))
+
+    change_str_main = (
+        f"| {TABLE_HEADERS[0].ljust(w_id)} "
+        f"| {TABLE_HEADERS[1].ljust(w_name)} "
+        f"| {TABLE_HEADERS[2].ljust(w_pr)} "
+        f"| {TABLE_HEADERS[3].ljust(w_qty)} |"
+    )
+
+    change_str_dif = (
+        f"|{'-' * (w_id + 2)}"
+        f"|{'-' * (w_name + 2)}"
+        f"|{'-' * (w_pr + 2)}"
+        f"|{'-' * (w_qty + 2)}|"
+    )
+
+    rows = []
+    for i in range(len(storage)):
+        row = (
+            f"| {ids[i].ljust(w_id)} "
+            f"| {names[i].ljust(w_name)} "
+            f"| {prices[i].ljust(w_pr)} "
+            f"| {quantitys[i].ljust(w_qty)} |"
+        )
+        rows.append(row)
+
+    res = "\n".join([change_str_main, change_str_dif, *rows])
+
+    return res