_{Previous Minesweeper puzzles}

_{Based off of Day 10 of the Minesweeper Advent Calendar on heptaveegesimal.com}

_{Difficulty (approximate): ★★★★☆}

_{Contains: Single mines (1 mine), Anti-mines (-1 mines), Double mines (2 mines)}

To get the $\color{green}✓$:

1. Solve the 8×8 Minesweeper grid (the bonus puzzle is just for more practice)
2. Show the steps used to fill in the grid.

So today, we have a pretty cool gimmick. What is the gimmick, you might ask? Today, the direct neighbors are counted twice, however the diagonal neighbors are counted once as always.

There are going to be no missing numbers from the actual puzzle since the actual puzzle is a really difficult puzzle on its own already.

An example:

Take this grid (contains only single mines) (Missing: 8x2, 9x1):

4
			12
	10
				$\color{white}.$
5

Now, how is everything placed in this example? Here’s how:

1. Note that mines that are orthogonal to a numbered cell are counted twice. Since there is only one way to add up to 4 and 5 using this info, we can place some single mines right away (m represents a single mine, x represents where a mine cannot go):

4	m
m	x		12
	10
m	m			$\color{white}.$
5	m

2. There is also only one way to get 12:

4	m	m	m	m
m	x	m	12	m
	10	m	m	m
m	m			$\color{white}.$
5	m

3. We can then deduce that there are mines at R3C1 and R4C3 because the total number of mines add up to 10 mines which is the only way to satisfy the 10 since we can’t have a mine at R2C2 which would make the 4 unsatisfiable, which means that 9 goes at R2C2:

4	m	m	m	m
m	9	m	12	m
m	10	m	m	m
m	m	m		$\color{white}.$
5	m

4. Due to the gimmick, there is only one way to place mines to get 8 (3 orthogonal mines having a total value of 6 mines added to 2 diagonal mines to get a total of 8 mines) so we can fill in the rest of the grid to get the final unique solution:

4	m	m	m	m
m	9	m	12	m
m	10	m	m	m
m	m	m	m	8
5	m	8	m	m

And that is the final and unique solution to our example grid.

Bonus example for more practice (not required for the green checkmark):

Contains: Single mine (1 mine), Double mines (2 mines)

Mine count: Single mine x13, Double mine x11

Missing numbers: N/A

	8			12
		13
7				13
		18		12
10					9
6		11	7

The (actual) puzzle:

Contains:

+---------------+---+
|Single mine    |x10|
+---------------+---+
|Double mine    |x20|
+---------------+---+
|Anti mine      |x14|
+---------------+---+
|Missing numbers|x0 |
+---------------+---+

Hint:

There are anti-mines at R2C4 and R2C5