Solution

app/main.py

@@ -1,34 +1,260 @@
 class Deck:
-    def __init__(self, row, column, is_alive=True):
-        pass
+    def __init__(
+            self,
+            row: int,
+            column: int,
+            is_alive: bool = True
+    ) -> None:
+        self.row = row
+        self.column = column
+        self.is_alive = is_alive
+
+    def __repr__(self) -> str:
+        return f"({self.row}, {self.column})"
 
 
 class Ship:
-    def __init__(self, start, end, is_drowned=False):
-        # Create decks and save them to a list `self.decks`
-        pass
+    def __init__(
+            self,
+            start: Deck,
+            end: Deck,
+            is_drowned: bool = False
+    ) -> None:
+        if start.row == end.row and start.column > end.column:
+            start, end = end, start
+
+        if start.column == end.column and start.row > end.row:
+            start, end = end, start
+
+        self.start = start
+        self.end = end
+        self.is_drowned = is_drowned
+        self.decks = self.get_full_ship_coords()
+
+    def is_ship_vertical(self) -> bool:
+        return self.start.column == self.end.column
+
+    def is_ship_horizontal(self) -> bool:
+        return self.start.row == self.end.row
+
+    def ship_length(self) -> int:
+        if self.is_ship_horizontal():
+            return 1 + (self.end.column - self.start.column)
+        if self.is_ship_vertical():
+            return 1 + (self.end.row - self.start.row)
+        raise ValueError(
+            f"Ship must be either horizontal or "
+            f"vertical! Got start={self.start}, end={self.end}"
+        )
+
+    def get_full_ship_coords(self) -> list[Deck]:
+        ship_length = self.ship_length()
+
+        is_vertical = self.is_ship_vertical()
+        is_horizontal = self.is_ship_horizontal()
+
+        if is_vertical or is_horizontal:
+            ship_coords = [self.start]
+
+            for index in range(1, ship_length):
+                row_to_append = self.start.row
+                column_to_append = self.start.column
+
+                if is_vertical:
+                    row_to_append += index
+                elif is_horizontal:
+                    column_to_append += index
+
+                ship_coords.append(Deck(row_to_append, column_to_append))
+
+            return ship_coords
+        raise ValueError("Ship must be either horizontal or vertical!")
+
+    def get_deck(
+            self,
+            row: int,
+            column: int
+    ) -> Deck:
+        for deck in self.decks:
+            if deck.row == row and deck.column == column:
+                return deck
+        raise ValueError(f"No deck with coords: ({row}, {column})")
+
+    def fire(
+            self,
+            row: int,
+            column: int
+    ) -> None:
+        deck = self.get_deck(row, column)
+        if not deck.is_alive:
+            return
+        deck.is_alive = False
+        if all(not deck.is_alive for deck in self.decks):
+            self.is_drowned = True
+
+
+class FleetValidator:
+    FIELD_SIZE = 10
 
-    def get_deck(self, row, column):
-        # Find the corresponding deck in the list
-        pass
+    def validate(self, ships: list[Ship]) -> None:
+        self._validate_fleet_size(ships)
+        self._validate_ships(ships)
+        self._validate_fleet_composition(ships)
+        self._validate_no_neighbors(ships)
 
-    def fire(self, row, column):
-        # Change the `is_alive` status of the deck
-        # And update the `is_drowned` value if it's needed
-        pass
+    def _validate_fleet_size(self, ships: list[Ship]) -> None:
+        if len(ships) != 10:
+            raise ValueError(
+                f"Invalid fleet size: expected 10 ships, got {len(ships)}."
+            )
+
+    def _validate_ships(self, ships: list[Ship]) -> None:
+        for idx, ship in enumerate(ships, start=1):
+            self._validate_orientation(ship, idx)
+            self._validate_length(ship, idx)
+            self._validate_in_bounds(ship, idx)
+
+    def _validate_orientation(self, ship: Ship, idx: int) -> None:
+        if not (ship.is_ship_horizontal() or ship.is_ship_vertical()):
+            raise ValueError(
+                f"Ship #{idx}: invalid orientation. "
+                f"Ships must be placed strictly "
+                f"horizontally or vertically. Got "
+                f"start={ship.start}, end={ship.end}."
+            )
+
+    def _validate_length(self, ship: Ship, idx: int) -> None:
+        length = ship.ship_length()
+        if not (1 <= length <= 4):
+            raise ValueError(
+                f"Ship #{idx}: invalid length. "
+                f"Ships must have length between 1 and 4. "
+                f"Got length={length} for start={ship.start}, end={ship.end}."
+            )
+
+    def _validate_in_bounds(self, ship: Ship, idx: int) -> None:
+        for deck in ship.decks:
+            if not (
+                    0 <= deck.row < self.FIELD_SIZE
+                    and 0 <= deck.column < self.FIELD_SIZE
+            ):
+                raise ValueError(
+                    f"Ship #{idx}: coordinate out "
+                    f"of bounds: ({deck.row}, {deck.column}). "
+                    f"Allowed range is 0..{self.FIELD_SIZE - 1}. "
+                    f"Ship start={ship.start}, end={ship.end}."
+                )
+
+    def _validate_fleet_composition(self, ships: list[Ship]) -> None:
+        lengths = [ship.ship_length() for ship in ships]
+        expected = {1: 4, 2: 3, 3: 2, 4: 1}
+        names = {
+            1: "single-deck",
+            2: "double-deck",
+            3: "three-deck",
+            4: "four-deck"
+        }
+
+        for length, exp_count in expected.items():
+            got = lengths.count(length)
+            if got != exp_count:
+                lengths_list = {
+                    _length: lengths.count(_length)
+                    for _length in sorted(set(lengths))
+                }
+                raise ValueError(
+                    f"Invalid fleet composition: "
+                    f"expected {exp_count} {names[length]} "
+                    f"ship(s), got {got}. "
+                    f"Actual counts by length: "
+                    f"{lengths_list}."
+                )
+
+    def _validate_no_neighbors(self, ships: list[Ship]) -> None:
+        forbidden = set()
+        shifts = [(dx, dy) for dx in (-1, 0, 1) for dy in (-1, 0, 1)]
+
+        for ship in ships:
+            decks = {(d.row, d.column) for d in ship.decks}
+
+            conflicts = decks & forbidden
+            if conflicts:
+                raise ValueError(
+                    f"Invalid ship placement: ships "
+                    f"overlap or touch at {sorted(conflicts)}."
+                )
+            for row, column in decks:
+                for dx, dy in shifts:
+                    nr, nc = row + dx, column + dy
+                    if 0 <= nr < self.FIELD_SIZE and 0 <= nc < self.FIELD_SIZE:
+                        forbidden.add((nr, nc))
 
 
 class Battleship:
-    def __init__(self, ships):
-        # Create a dict `self.field`.
-        # Its keys are tuples - the coordinates of the non-empty cells,
-        # A value for each cell is a reference to the ship
-        # which is located in it
-        pass
-
-    def fire(self, location: tuple):
-        # This function should check whether the location
-        # is a key in the `self.field`
-        # If it is, then it should check if this cell is the last alive
-        # in the ship or not.
-        pass
+    def __init__(
+            self,
+            ships: list[tuple[tuple, tuple]]
+    ) -> None:
+        ships_objects = self._build_ships(ships)
+        FleetValidator().validate(ships_objects)
+        self.field = self._build_field_dict(ships_objects)
+
+    def _build_ships(
+            self,
+            ship_list: list[tuple[tuple, tuple]]
+    ) -> list[Ship]:
+        return [
+            Ship(Deck(*start_coords), Deck(*end_coords))
+            for start_coords, end_coords in ship_list
+        ]
+
+    def _build_field_dict(
+            self,
+            ship_list: list[Ship]
+    ) -> dict:
+        fields_dict = {}
+        for ship in ship_list:
+            for deck in ship.decks:
+                fields_dict[(deck.row, deck.column)] = ship
+        return fields_dict
+
+    def fire(self, location: tuple) -> str:
+        try:
+            ship = self.field[location]
+            ship.fire(*location)
+            if ship.is_drowned:
+                return "Sunk!"
+            return "Hit!"
+        except KeyError:
+            return "Miss!"
+
+    def print_field(self) -> None:
+        # порожні поля
+        deck = [
+            ["~" for _ in range(FleetValidator.FIELD_SIZE)]
+            for _ in range(FleetValidator.FIELD_SIZE)
+        ]
+
+        # кораблі
+        for location, ship in self.field.items():
+            row, column = location
+            cur_deck = ship.get_deck(row, column)
+
+            if ship.is_drowned:
+                deck[row][column] = "x"
+            elif not cur_deck.is_alive and not ship.is_drowned:
+                deck[row][column] = "*"
+            elif cur_deck.is_alive:
+                deck[row][column] = u"\u25A1"
+
+        # нумерація поля
+        for i, row in enumerate(deck):
+            if i == 0:
+                print(
+                    " ", " ".join(
+                        str(num) for num in range(
+                            FleetValidator.FIELD_SIZE
+                        )
+                    )
+                )
+            print(i, " ".join(row))