perplexus.info :: Logic : Four Squared

Four Squared (Posted on 2006-10-26)

        Grid A                    Grid B      
     A   B   C   D             A   B   C   D  
   +---+---+---+---+         +---+---+---+---+
1  |   |   |   |   |      1  |14 |23 |34 |14 |
   +---+---+---+---+         +---+---+---+---+
2  |   |   |   |   |      2  |31 |42 |26 |26 |
   +---+---+---+---+         +---+---+---+---+
3  |   |   |   |   |      3  |22 |24 |44 |29 |
   +---+---+---+---+         +---+---+---+---+
4  |   |   |   |   |      4  |12 |32 |19 |16 |
   +---+---+---+---+         +---+---+---+---+

The numbers 1 to 16 are to be placed in grid A, so that consecutive numbers are not adjacent in any direction, including diagonally. Nor do they appear in the same row, column or any diagonal.

The number in each cell of grid B is the sum of the horizontal and vertical neighbors of the corresponding cell in grid A.

NB. The letters and numbers around the edge of the grid serve no purpose for the solver. They are to be used for identifying cells in the solution.

See The Solution Submitted by Josie Faulkner

Rating: 4.4167 (12 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)

re(2): computer solution

| Comment 8 of 18 |

(In reply to re: computer solution by Josie Faulkner)

In fact the caveat against adjacent numbers being consecutive and against columns or rows having consecutive numbers was not used by the program. The result came out that way anyway, but was not used in finding the unique solution. Only the information in grid B was used.

Posted by Charlie on 2006-10-27 09:22:36

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