Logic Masters Deutschland e.V.

Rules:
Blacken some cells and then place a single letter into every empty cell such that each of the letters ‘A’, ‘B’, and ‘C’ appears exactly once in each row and each column. Some cells already contain a letter; these cells must either be left alone or blackened (which removes that letter from the cell). The letters outside the grid indicate the first letter that can be seen in the respective row or column from the respective direction. When numbers are given to the left of (and above) the main grid, they represent the lengths of all the contiguous blackened cell blocks in the corresponding row (or column). The lengths are given in order from left to right (or top to bottom), and cell blocks must contain at least one unblackened cell between them. “?” has the same mining as numbers.