Hint displays

By left clicking on the corresponding button in the Toolbar the user can select a specific algorithm to be applied to search for a hint. Alternatively the "?" button in the Toolbar or the "Give hint" option in the Edit menu can be used. In the latter cases the program will use its current search strategy and find an appropriate hint using any of the currently active algorithms. The resulting hint is then displayed.

The hint display provides two classes of information about the patterns found: it can colour the Toolbar to show which algorithm found the hint, and it can colour the cells and candidates involved in the hint. Depending on the level of help they want, the users can specify the amount of detail these provide. The hint display is selected using the "Set hint level" option in the File menu.

For the hints in the Sudoku program SourGumdrop I was able to display the reason that candidates could be deleted - i.e. the pattern of some candidates which meant that others could not be the solution and hence could be removed. For half of the current Kakuro methods this is not possible: for these algorithms candidates can be deleted because they are incompatible with the row or column combinations, not because of patterns in the other candidates. So, SourGumdropK cannot always display the reason for the hints it finds - only the candidates which can be removed.

Setting "Highlight candidates" puts the program into a mode in which it will identify the candidates which can be removed in red and, where possible, the causing candidates in green.

Setting "Highlight cells" puts the program into a mode in which it will identify cells which cause the pattern (yellow) and which can have candidates removed (pink) (see Figure 2).