Place one of the four letters A, B, C or D in each of the blue-coloured cells. No letter can be horizontally or vertically adjacent to itself. The yellow-coloured tables above and to the left of the grid indicate how many times each letter appears in that column or row.

This is an extended version of ABCD.

				A	3	2	0	2	2	2	0	3	1
				B	2	1	3	0	0	1	3	0	2
				C	1	2	1	3	2	3	1	2	1
	A	B	C	D	0	1	2	1	2	0	2	1	2
	2	0	4	3
	4	4	1	0
	3	2	2	2
	3	3	2	1
	1	0	4	4
	2	3	3	1

(In reply to Solution by Dej Mar)

DM: I'm new to this puzzle form, but I interpreted the second sentence ("No letter can be horizontally or vertically adjacent to itself") to exclude consecutive cells (row or column) with the same letter.  Your solution would not meet that criterion.

Posted by ed bottemiller on 2008-03-07 15:26:45