Logic Masters Deutschland e.V.

Rules
Normal sudoku rules apply.
Digits must not repeat along the positive diagonal.
A and B represent two different numbers.
Clues outside the grid are simultaneously X-sums clues, sandwich clues, and skyscrapers clues.
X-sums: clues indicate the sum of the first X digits, where X is the first seen digit.
Sandwich: clues indicate the sum of the digits between the 1 and the 6 in that row/column.
Skyscrapers: clues indicate how many digits are "seen" by the clue looking into its row/column. Digits are visible when they are larger than all digits before them.

Play this puzzle on SudokuPad