Code
The highlighted line runs next. The pill shows the live values in the running call.
Cost
Work done so far, and how the three solutions compare
Board
Tinted cells = the unit(s) being checked; red = the clashing pair
The highlighted line runs next. The pill shows the live values in the running call.
Work done so far, and how the three solutions compare
Tinted cells = the unit(s) being checked; red = the clashing pair
Keyboard: ← → step, Space play or pause (outside the board box). Edit the board as 9 lines of 9 characters, digits 1–9 or "." for empty; brackets, quotes and commas are ignored, so the problem's format pastes straight in. Empty cells are skipped silently, so the trace only stops on filled cells.