Merge pull request #250 from ikostan/exercism-sync/8e85932bb96c7ce7

[Sync Iteration] python/flower-field/8

Author: ikostan

solutions/python/flower-field/8/flower_field.py

@@ -0,0 +1,125 @@
+"""
+Flower Field is a compassionate reimagining of the popular game Minesweeper.
+
+This module provides helpers to validate and annotate a rectangular garden
+representation, where each row is a string comprised of spaces and ``*``
+characters. A ``*`` denotes a flower; a space denotes an empty square.
+
+The goal is to compute numeric hints indicating how many flowers are
+adjacent (horizontally, vertically, diagonally) to each square.
+"""
+
+
+def annotate(garden: list[str]) -> list[str]:
+    """
+    Annotate a garden with counts of adjacent flowers.
+
+    Expects a rectangular list of strings containing only spaces and ``*``.
+    Validation errors raise a :class:`ValueError`.
+
+    :param list garden: A list of equal-length strings representing the garden.
+        ``*`` marks a flower; space marks empty.
+    :returns: An annotated garden of the same shape. Empty squares are
+        replaced by digits (``"1"``–``"8"``) when adjacent to flowers;
+        squares with zero adjacent flowers remain spaces. Flowers
+        (``*``) are preserved.
+    :rtype: list[str]
+    :raises ValueError: If the garden is non-rectangular or contains
+        invalid characters.
+    """
+    # empty list
+    if not garden:
+        return []
+
+    # raise an error when the board receives malformed input
+    _validate(garden)
+
+    new_garden: list[str] = garden.copy()
+    for i_row, row in enumerate(new_garden):
+        for i_col, char in enumerate(row):
+            if char == " ":
+                flower_count = 0
+                flower_count += _calc_surrounding_flowers(i_row, i_col, new_garden)
+
+                if flower_count != 0:
+                    new_garden[i_row] = (
+                        new_garden[i_row][:i_col]
+                        + str(flower_count)
+                        + new_garden[i_row][i_col + 1 :]
+                    )
+
+    return new_garden
+
+def _calc_surrounding_flowers(i_row: int, i_col: int, garden: list[str]) -> int:
+    total: int = 0
+
+    if i_col - 1 >= 0 and garden[i_row][i_col - 1] == "*":
+        total += 1
+
+    if i_col + 1 < len(garden[i_row]) and garden[i_row][i_col + 1] == "*":
+        total += 1
+
+    if i_row - 1 >= 0 and "*" in garden[i_row - 1]:
+        if i_col > 0 and garden[i_row - 1][i_col - 1] == "*":
+            total += 1
+        if garden[i_row - 1][i_col] == "*":
+            total += 1
+        if i_col + 1 < len(garden[i_row]) and garden[i_row - 1][i_col + 1] == "*":
+            total += 1
+
+    if i_row + 1 < len(garden) and "*" in garden[i_row + 1]:
+        if i_col > 0 and garden[i_row + 1][i_col - 1] == "*":
+            total += 1
+        if garden[i_row + 1][i_col] == "*":
+            total += 1
+        if i_col + 1 < len(garden[i_row]) and garden[i_row + 1][i_col + 1] == "*":
+            total += 1
+
+    return total
+
+
+def _calc_flower_bottom(i_row: int, i_col: int, garden: list[str]) -> int:
+    """
+    Count flowers in the three cells directly below the current position.
+
+    Checks the bottom-left, bottom, and bottom-right neighbors when the row
+    below exists and contains any flowers.
+
+    :param int i_row: Current row index.
+    :param int i_col: Current column index.
+    :param list garden: The garden as a list of strings.
+    :returns: Number of ``*`` cells among the three lower neighbors.
+    :rtype: int
+    """
+    flower_count = 0
+
+    if i_row + 1 < len(garden) and "*" in garden[i_row + 1]:
+        # bottom-left
+        if i_col > 0 and garden[i_row + 1][i_col - 1] == "*":
+            flower_count += 1
+        # bottom
+        if garden[i_row + 1][i_col] == "*":
+            flower_count += 1
+        # bottom-right
+        if i_col + 1 < len(garden[i_row]) and garden[i_row + 1][i_col + 1] == "*":
+            flower_count += 1
+    return flower_count
+
+
+def _validate(garden: list[str]):
+    """
+    Validate the garden shape and contents.
+
+    Ensures the input is rectangular and contains only spaces and ``*``.
+
+    :param list garden: A list of equal-length strings to validate.
+    :raises ValueError: If rows have differing lengths or contain characters
+        other than space or ``*``.
+    """
+    garden_length = len(garden[0])
+    for row in garden:
+        # when the board receives malformed input
+        # garden is not a rectangle due to inconsistent row length
+        # or contains invalid chars inside the row
+        if len(row) != garden_length or not all(char in " *" for char in row):
+            raise ValueError("The board is invalid with current input.")