Logic Masters Deutschland e.V.

Place a digit from {1, 3, 9} on each cell in the 7 x 7 grid. In total, digit "1" appears exactly in 13 cells and digit "3" appears exactly in 31 cells.

Digit "1" must appear less than 3 times in each row and each column. Digit "9" must also appear less than 3 times in each row and each column. Additionally, every cell with digit "3" must be adjacent (orthogonally) to at least one cell with digit "1" or "9".

The 7x7 grid is divided into 13 cages. The sum of all digits in any cage is either 1, 3, 11, 13, or 33; some of the sums are given on the top-left of the cage. All cells with an "X" contain the same digit and all cells with a "Y" contain the same digit.

Have fun and God bless.

sudokupad link