All Questions
Tagged with solvability logical-deduction
13 questions
4
votes
2
answers
501
views
Beach Umbrellas puzzle: did I make a mistake or is Brainzilla wrong?
https://www.brainzilla.com/logic/logic-grid/beach-umbrellas/ has the following puzzle:
Four families are going to the beach in the morning and are bringing
their family-size umbrellas. Which family ...
3
votes
1
answer
782
views
Possible parity for sliding puzzle
As you can see, I have a sliding 5x5 puzzle, but no matter what way I scramble it and solve it again, I always seem to have two pieces that need to be swapped. Is there a way to swap the two pieces? (...
user81426
0
votes
1
answer
192
views
Does every validly posed Sudoku have at least one solution and if not what is the minimum number of givens for it to be unsolvable? [duplicate]
Does every validly posed Sudoku (doesn't break any Sudoku rules so only no duplicate 1 to 9 in rows, columns or square) have at least one solution, and if not, what is the minimum number of givens for ...
- 219
15
votes
2
answers
3k
views
Hotaru Beam Puzzle: Is it impossible?
I saw this puzzle on Twitter by user @lilva_0419 and I personally feel that it is impossible to solve. Can you prove me wrong (or right)?
Source on Twitter
Try it online
Rules (see Wikipedia):
...
- 273
2
votes
2
answers
439
views
Logical Sudoku - How to tell when fully deducted?
I'm working a program that should generate bad ass sudoku puzzles. Recently I noticed there's a thing called "logical sudoku", which means it can be logical-deducted all the way to solution.
The ...
- 163
3
votes
1
answer
208
views
Stuck on (a couple of) diagramless kakuros
I was working through OAPC 6 (http://oapc.wpc2009.org/archive.php?id=46). I was having trouble with the diagramless kakuros. The rules for this puzzle are as follows: Place the numbers $1-n$ (7 and 9 ...
- 147
3
votes
2
answers
215
views
Stuck on a Tapa (variation)
I am stuck on a Tapa puzzle. I have tried solving it a number of times and keep running into the same problems. I am starting to wonder if it is solvable at all. As far as the puzzle itself goes, best ...
- 147
8
votes
2
answers
2k
views
Stuck on a puzzle
I have been working on a Knapp Daneben Tapa, where each clue is wrong by exactly one unit. I have tried it a few times and keep running into the same problem. I think I am solving it deductively/not ...
- 147
4
votes
5
answers
1k
views
Systematically solving a certain logic puzzle: win prize B when the truth of your statements relates to prize A
I came along this puzzle somewhere it a logic-related lecture:
There are two prizes: Prize A and prize B.
When you make a true statement, then you win prize A.
When you make a false statement, then ...
- 1,710
10
votes
4
answers
2k
views
JonMark Perry's Grid Logic Puzzle
Consider the following puzzle type proposed by JonMark Perry.
Start with a square grid of arrows, each one pointing in one of the four cardinal directions. For example:
You start at the top left. ...
- 118k
0
votes
2
answers
1k
views
Connect the Dots Problem
Using the image above, the rules are every dot must have a line through it, no diagonal lines, no crossing over lines, no backtracking, no going out of bounds, and no picking up the pencil to start at ...
10
votes
1
answer
378
views
Web of Spirits - a puzzle of romance
Spirit Web:
Can you figure out the interconnected web of affections among these characters using the provided clues?
Basic Rules:
1: There are exactly three existing relationships.
2: No character in ...
- 3,949
60
votes
4
answers
85k
views
What is the maximum number of solutions a Sudoku puzzle can have?
I've seen Sudoku puzzles that can be solved two different ways. Referring to a traditional 9x9 grid:
Is it possible for a Sudoku puzzle to have more than two solutions? If so, what is the maximum ...
- 2,533