Light up the Christmas Tree
(Published on 2. December 2023, 09:49 by Tobias Brixner)
Puzzle link: Play on CTC SudokuPad.
Rules: Normal Sudoku rules apply, i.e., place the digits 1 to 9 once each into each row, column, and 3×3 box.
Circles contain the digits 1 to 9 once each. Clues outside of the grid give the sum of circled digits in that row or column.
Light up the Christmas tree by drawing an uninterrupted "power" line that starts at the circled 1, connects orthogonally adjacent cells such that it visits all circled digits ("electric candles") in ascending order, and ends at the circled 9 with no cell visited twice. Between circled digits N and N+1, the power line must make exactly N turns by 90 degrees. Turns within circles are not counted. A cage clue indicates how many turns exactly the power line makes in that cage.
All cells (including circled cells) that contain a left turn, when following the power line from start to end, share the same parity, i.e., they are either all odd or all even, and all cells that contain a right turn share the other parity.
On the given green lines, independent of the power line, adjacent digits differ by 5 or more.
Background: The arrangement of the green and yellow clues is supposed to resemble (more or less) a Christmas tree with candles. Concerning the solve experience, maybe you want to imagine the decoration procedure of the tree and then the opening of gifts, step by step, while the surroundings might become a bit messy from the various gift wrapping materials that accumulate.
Solution code: All digits of row 2 (from left to right) followed by column 9 (from top to bottom) without spaces.
Comments
on 2. December 2023, 20:17 by Kversten
Figuring out the "power line" was really cool, and the last phase was also a real challange untill entering the last two digits. Overall, it was a very interesting puzzle!
