zakarya/puzzles
1
0
Fork 0
mirror of git://git.tartarus.org/simon/puzzles.git synced 2025-04-21 16:05:44 -07:00
Code Issues Packages Projects Releases Wiki Activity

Filling: remove directional bias in grid generation.

Browse Source 
The method of generating a solved Filling grid (before winnowing
clues) is to loop over every square of the board, and for each one, if
it has a neighbour which is part of a different region of the same
size (i.e. the board is not currently legal), fix it by merging with
one of its neighbours. We pick a neighbour to merge with based on the
size of its region - but we always loop over the four possible
neighbours in the same order, which introduces a directional bias into
the breaking of ties in that comparison.

Now we iterate over the four directions in random order.
This commit is contained in:
Simon Tatham
2021-03-29 20:49:17 +01:00
parent 1fcb61cffe
commit 083de051cb
1 changed files with 7 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
filling.c
View File

@ -414,10 +414,15 @@ retry:
int merge = SENTINEL, min = maxsize - size + 1; int merge = SENTINEL, min = maxsize - size + 1;
bool error = false; bool error = false;
int neighbour, neighbour_size, j; int neighbour, neighbour_size, j;
int directions[4];
for (j = 0; j < 4; ++j)
directions[j] = j;
shuffle(directions, 4, sizeof(int), rs);
for (j = 0; j < 4; ++j) { for (j = 0; j < 4; ++j) {
const int x = (board[i] % w) + dx[j]; const int x = (board[i] % w) + dx[directions[j]];
const int y = (board[i] / w) + dy[j]; const int y = (board[i] / w) + dy[directions[j]];
if (x < 0 || x >= w || y < 0 || y >= h) continue; if (x < 0 || x >= w || y < 0 || y >= h) continue;
neighbour = dsf_canonify(dsf, w*y + x); neighbour = dsf_canonify(dsf, w*y + x);