Find bounding boxes of connected houses

You are given a 2D grid representing a map, where each cell is either 1 (part of a house) or * (empty). A house is a maximal group of 1 cells connected 4-directionally (up, down, left, right).

Unlike a standard matrix, the grid is ragged: each row may have a different number of columns.

Task

Return the bounding rectangle of every house as a pair:

• top-left coordinate (minimum row, minimum column among the house’s cells)
• bottom-right coordinate (maximum row, maximum column among the house’s cells)

Coordinates must be formatted like spreadsheet cells:

• Rows are labeled with uppercase letters: A for row 0, B for row 1, …
• Columns are labeled with 1-based numbers: column 0 → 1 , column 1 → 2 , …

So row 0, col 1 is A2.

Input

• A list of rows, where each row is a list (or string) of characters from { '1', '*' } .
• Rows can have different lengths.

Output

• A list of house bounding boxes, each represented as a pair of strings: [topLeft, bottomRight] .
• The order of houses may be arbitrary unless otherwise specified.

Example

Grid (ragged):

• Row A: [* * * * 1 1 1 * *]
• Row B: [* 1 1 * *]
• Row C: [* * 1 1 * * *]

Interpretation: a cell exists only where a row has that column index.

Notes / Edge cases

• A neighbor cell is valid only if it is within the bounds of its row.
• A house may consist of a single cell.
• Assume the number of rows can exceed 26; specify how you will label rows beyond Z (e.g., AA , AB , ...) or state that inputs are limited to 26 rows.

Constraints (you may assume)

• Total number of cells across all rows is up to a reasonable limit (e.g., <= 2e5 ).

Design an algorithm to find all houses and their bounding boxes.