Logic Masters Deutschland e.V.

This is a hybrid puzzle combining ABC-Box with Skyscrapers, inspired by this puzzle by ibag. For those who are familiar with both puzzle types, the yellow cells are a skyscraper grid, the white cells are an ABC-Box grid, and letters adjacent to yellow cells are crypto skyscraper clues from 1-3. For everyone else, here are the rules:

White cells are an ABC-Box: fill the white cells with A B and C according to clues outside the grid. Letter clues indicate which letter to use next, but not how many. Number clues indicate how many of the next letter to use, but not what the letter is. ? clues indicate some number of some letter, to be determined. Consecutive clues must use different letters (i.e. 2A1 cannot mean AAAC).

Yellow cells are a Skyscrapers grid. Digits from 1-4 represent the heights of buildings, with taller buildings hiding smaller buildings behind them. Digits may not repeat in a row/column.

The ABC clues adjacent to the yellow squares are crypto clues for the Skyscrapers grid, representing values from 1-3. These clues indicate how many buildings can be "seen" when looking in that direction. i.e. AC2431BB would mean C = 2 and B = 3.

Solve on Penpa

Answer Check and Solution Code expect uppercase letters to be used.