# HG changeset patch # User Shlomi Fish # Date 1338635035 -10800 # Node ID f78ef4e9c75ca9214098d5e4e26bb85ecf1df06c # Parent 910862df7259e4f1d4dc085562c36e2760193b71 Add another item diff --git a/docs/Nurikabe_Strategies.txt b/docs/Nurikabe_Strategies.txt --- a/docs/Nurikabe_Strategies.txt +++ b/docs/Nurikabe_Strategies.txt @@ -24,7 +24,7 @@ limits of its number), an island can only expand into one cell, then that cell will be white. -#. If an Island reaches certain points that reaching them consumes all of its +#. If an Island reaches certain points which consume all of its number, then its white edge points can be marked with black in the opposite direction to its extent. @@ -46,3 +46,25 @@ We can see that the island should expand into the leftmost gray/unknown cell or else it will need to take a costly detour which will consume the rest of its number. + +#. Islands that can expand in several different manners must mark all the +common black cells inflected by these ways in this way. For example: + ++------ +|[2][G] +|[G][G] + +The lower-right [G] cell must be black because it will be black whether the +2 expands to the right or to the bottom. + +In addition, if we have: + + x1 x2 x3 x4 +y1 [B][B][B] +y2 [B][4][W][B] +y3 [B][G][W][B] +y4 [G][G][B] + +The the 4-cell region can only expand into (x2,y3) or (x3,y4) so +[G](x2,y4) must be black. +