1 | 2 | 4 | ||
2 | ||||
22 |
Source: Original. [Thanks to Mark Rickert for updating part 2 to a solvable problem.]
Part 1 has solutions for sums: -5,-3,-1, 1,3,5,11,13. Here's an example of each:
Sum of -55-1-9 - - - 3-2-6 - - - 7-4-8Sum of -3
1+3-7 + + - 5-2-6 - - - 9-8-4Sum of -1
1+4-6 + + - 7-3-5 - - - 9-8-2Sum of 1
2+4-5 + - - 7-9+3 - + - 8-6-1Sum of 3
4+6-7 + + - 8-2-3 - - - 9-5-1Sum of 5
2-1+4 - - - 3-5+7 + + + 6-9+8Sum of 11
8-1+4 - + + 6+3+2 + + + 9+7-5Sum of 13
7-2+8 - + + 3+6+4 + + + 9+5-1
Part 2 has one solution:
4-1-2 + - - 6-7+3 - + + 9+8+5
Claudio Baiocchi extended part 1 to look for diagonal solutions as well, finding a solution to a previous problem on this site.