[Feature] Add get_word_path function to word_search.py

[maknelso]

Feature description

I would like to add a new function, lets called get_word_path to backtracking/word_search.py.

Existing exits_word function is great for bool checks but users may want to know the specific coordinates for highlighting or path finding.

The new function will:

1. Returns a list[tuple[int,int]] | None instead of bool
2. Use a dedicated backtracking approach to capture the coordinates.
3. Include modern type hints and comprehensive doctests.

I have tested implementation ready. May I submit a PR?

[Jeeva1070]

def get_word_path(board: list[list[str]], word: str) -> list[tuple[int, int]] | None:
"""
Finds the path of a word in a 2D grid using optimized backtracking.
Returns a list of (row, col) tuples or None if not found.

>>> board = [["A","B","C","E"],["S","F","C","S"],["A","D","E","E"]]
>>> get_word_path(board, "ABCCED")
[(0, 0), (0, 1), (0, 2), (1, 2), (2, 2), (2, 1)]
>>> get_word_path(board, "SEE")
[(1, 3), (2, 3), (2, 2)]
>>> get_word_path(board, "XYZ") is None
True
"""
if not board or not board[0] or not word:
    return None

rows, cols = len(board), len(board[0])
path: list[tuple[int, int]] = []

def backtrack(r: int, c: int, index: int) -> bool:
    # Base case: entire word found
    if index == len(word):
        return True

    # Boundary and match check
    if not (0 <= r < rows and 0 <= c < cols) or board[r][c] != word[index]:
        return False

    # Mark as visited in-place
    temp = board[r][c]
    board[r][c] = "#"
    path.append((r, c))

    # Explore neighbors: Up, Down, Left, Right
    for dr, dc in [(-1, 0), (1, 0), (0, -1), (0, 1)]:
        if backtrack(r + dr, c + dc, index + 1):
            # We found the path, don't clean up board yet so we can return
            board[r][c] = temp 
            return True

    # Backtrack: Restore state if path not found through this cell
    path.pop()
    board[r][c] = temp
    return False

for i in range(rows):
    for j in range(cols):
        if backtrack(i, j, 0):
            return path

return None

[maknelso]

I wanted to contribute.
May I contribute?

I spot a few issues with the proposed code.

[Jeeva1070]

Sure