Battleships Even/Odd/en
Aus Puzzlewiki
Instructions
Place the given fleet horizontally or vertically into the grid. If a ship is placed on even number of cells, it must be placed on grey cells only. If a ship is placed on odd number of cells, it must be placed on white cells only. Numbers on the sides reveal the number of ship segments on the respective row or column. Grey cells outside the grid contain even number, white cells outside the grid contain odd number.
It is enough to place all ships correctly, You do not have to write all numbers around the grid.
History
This puzzle type was used in WPC 2010 Poland.