Typed Logic Author
Posts: 241
Location: Indonesia | sanket - 2011-05-07 9:44 PM
Also the rules of hitori say that a number cannot appear more than once.
So can we use the reverse rule : Circling a particular number (or shading in yellow as in above case) if its another occurence in the same row/column has been shaded (in grey color as in above) because this ensures that the number will always occur once (and cannot appear 'zero' times) ?
Not necessarily. Try this:
1112
2341
1213
2421
Observe C3. Both of its 1s are shaded, leaving no 1 remaining.
To above: The first is yes if the solution is guaranteed to be unique (but no otherwise), the second is no. |