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use Octans::Neighbors;
subset File of Str where *.IO.f;
# Cells as defined by fornax format.
constant $PATH = '.';
constant $BLOK = '#';
constant $DEST = '$';
constant $STRT = '^';
constant $VIS = '-';
constant $CUR = '@';
constant $CURPATH = '~';
sub MAIN(File $input) {
my @maze = $input.IO.lines.map(*.comb);
die "Inconsistent maze" unless [==] @maze.map(*.elems);
put "rows:{@maze.elems} cols:{@maze[0].elems}";
dfs(@maze, 0, 0);
}
sub dfs(
@maze, Int $y, Int $x, @visited?, @cur-path? --> Bool
) {
# If @visited was not passed then mark the given cell as visited
# because it's the cell we're starting at.
@visited[$y][$x] = True unless @visited;
@cur-path[$y][$x] = True unless @cur-path;
# neighbor block loops over the neighbors of $y, $x.
neighbor: for neighbors(@maze, $y, $x).List.pick(*) -> $pos {
# Move on to next neighbor if we've already visited this one.
next neighbor if @visited[$pos[0]][$pos[1]];
# Printing Marker cells.
given @maze[$pos[0]][$pos[1]] {
when $DEST { print "|" }
when $BLOK { print "!" }
}
# Print the maze on every iteration.
for 0..@maze.end -> $j {
for 0..@maze[0].end -> $k {
if @maze[$j][$k] eq $STRT | $DEST {
print @maze[$j][$k];
} else {
if $j == $pos[0] and $k == $pos[1] {
print "@";
} else {
print(
@cur-path[$j][$k]
?? "~" !! @visited[$j][$k] ?? "-" !! @maze[$j][$k]
);
}
}
}
}
print "\n";
given @maze[$pos[0]][$pos[1]] {
when $DEST { exit; }
when $PATH|$STRT {
@visited[$pos[0]][$pos[1]] = @cur-path[$pos[0]][$pos[1]] = True;
dfs(@maze, $pos[0], $pos[1], @visited, @cur-path);
@cur-path[$pos[0]][$pos[1]] = False;
}
}
}
}
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