All Questions
Tagged with grid-deduction combinatorics
10 questions
5
votes
2
answers
565
views
Number of 3x3 One Up puzzles
Rodolfo Kurchan created a wonderful new grid puzzle called One Up that you can play on his website. There is one main rule:
Each horizontal and vertical sequence of N cells between walls, must contain ...
- 37.6k
-4
votes
1
answer
128
views
Binary Grid Challenge and X & O Conundrum
You are given a 5x5 grid with some cells filled with either "X" or "O". Your goal is to fill the remaining cells with "X" or "O" following these rules:
Each row ...
- 109
8
votes
2
answers
614
views
How many Nonconsecutive Sudoku solutions are there?
Consecutive Sudoku is a variant with the additional rule that orthogonally adjacent numbers are consecutive if and only if there is a dot/bar on the line between them. A Nonconsecutive Sudoku is one ...
- 10.6k
16
votes
2
answers
823
views
XV Sawtooth Sudoku
Please find below a variant Sudoku puzzle, based on a combinatorics problem I was having a look at. The timing is right, as I recently saw @BeastlyGerbil back in chat, and I know that user is a big ...
- 29.2k
7
votes
1
answer
336
views
A 3x3 grid with common factors
A $3 \times 3$ grid $G$ is filled with every number from the set $\{2,3,5,6,7,11,14,15,30\}$. Now a new $3 \times 3$ grid $H$ is formed, such that $H_{ij}$ is the number of neighbors of $G_{ij}$ that ...
- 37.6k
10
votes
4
answers
1k
views
Deriving a 3x3 grid from another one
A $3 \times 3$ grid $G$ is filled with every number from $1$ to $9$. Now a new $3 \times 3$ grid $H$ is formed, such that $H_{ij}$ is the number of neighbors of $G_{ij}$ that are greater than $G_{ij}$....
- 37.6k
2
votes
0
answers
527
views
A robot moving on a grid. Part 2
This is an extension of the discussion
A robot is placed on a grid point. At each move the robot must take three steps along the edge of the grid. After each step the robot must turn right. Lengths of ...
- 1,703
5
votes
3
answers
872
views
Will you be the first to get free?
It is your first day in prison and you are approached by a guard having a hunch for puzzles.
He tells you that he gives every new prisoner the chance to be freed if they can present him with a version ...
- 311
4
votes
1
answer
163
views
Finding the Missing Word in a Crossword
On each of the 25 cells of this board, place one of the letters A, C, M or S so that, in alphabetical order, nine of the ten words that can be read down or across are the following:
AACAC
AMCAS
...
- 19.2k
4
votes
1
answer
679
views
Albrecht Durer Inspired Magic Square
A magic square is an n-dimensional matrix in which each row, column, and main diagonal sums to the same 'magic number' (denoted by s). A normal magic square uses each of the numbers from 1 to n ...
- 43