Complete a small grid so that the four marked cells form the corners of an axis-aligned square.
Problem
You are given a square grid containing exactly four marked cells represented by # and all other cells represented by ..
Your task is to add the minimum number of # cells so that the four original marked cells become the corners of an axis-aligned square. The square may be larger than the current arrangement, but its sides must be parallel to the grid axes.
If the four existing marked cells already form a square, the grid should remain unchanged.
What to output
Return the final grid after placing the extra marks.
Notes
- The four original
#cells are guaranteed to be positioned so that a valid square can be completed. - The answer is unique up to the required placement of the missing corners.
Input Format
- The first line contains an integer
t, the number of test cases. - For each test case, four lines follow, each containing four characters
.or#describing the grid.
Output Format
For each test case, output the completed 4 x 4 grid after adding the missing # cells.
Constraints
1 <= t <= 100- Each grid is
4 x 4 - Exactly four cells in the grid are marked with
# - A valid axis-aligned square can always be formed by adding cells
Example 1
Input
1 .... .#.. .... ..#.
Output
.... .#.# .... .#.#
Explanation
The marked cells are on different rows and columns. Completing the square requires adding the other two corners at the matching row/column intersections.
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