Logic Masters Deutschland e.V.

This puzzle is one that was posted earlier, but I wasn't quite satisfied with the previous version, so I've made some changes. I deleted the known numbers and changed a clue so that the grid clues only have nine 9s.




RULES
1️⃣：Normal sudoku rules apply.
2️⃣：Clues outside the grid must follow only one of the rules 【Numbered room,Sandwiche,X-sum and Skyscraper 】,and the same kind of the clues have the same colour.
①,Numbered room:Clues outside the grid indicate the digit which has to be placed in the Nth cell in the corresponding direction, where N is the digit placed in the first cell in that direction.
②,Sandwich:Digits between 1 and 9 in the indicated row or column must sum to the indicated value.
③,X-sum:Clues at the edge of the grid show the sum of the first X digits, where X is the first seen digit.
④,Skyscrapers:Each digit in the grid represents the height of a building in its cell. Taller buildings obstruct the view of shorter ones behind them. Clues outside the grid give the number of buildings visible from that vantage point in the clue's row or column.
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