Place a digit from 1 to N, in an NxN grid, into each of the empty cells so that each digit appears exactly once in each row and column. White dots indicate that the 2×2 area around them contain exactly one consecutive pair of digits. Black dots indicate that the 2×2 area around them contain at least two consecutive pairs of digits. Not all dots are given. Repeats are allowed, e.g., 2-4-5-6 is valid with 4-5 and 5-6, and so is 2-5-6-5.
(Rules and example from WPC 2017 IB)
History of the puzzle
Appearances in the past WPCs
- WPC 2017/Round 2 by Ashish Kumar