```My solution is in two parts:
-divide and conquerer until a '@' is found
-use a recursive backtracker starting from the seed coord. found in
step 1.

I am not positive about my worst-case analysis on lookups.

-C

\$map = File.new(ARGV[0]).inject([]){|a,line| a << line.split("")}
#vertical line
m = lambda {|x| (1..10).detect{|y| \$map[y][x] == '@'}}
#horizontal line
n = lambda {|y| (1..20).detect{|x| \$map[y][x] == '@'}}
#find a coordinate with an '@'; worst case 118 lookups
seed =
[[n.call(5),5],[n.call(6),6],[10,m.call(10)],[6,m.call(6)],[3,m.call(3)],[8,m.call(8)],\
[16,m.call(16)],[13,m.call(13)],[18,m.call(18)]].detect{|a| a[1]
!= nil and a[0] != nil}
#recursive maze solver; worst case 80 lookups
\$visits = {}
def m_solver(a,found)
x,y = a[0],a[1]
return if found >= 10
if \$visits["#{y},#{x}"] == nil
puts "#{x-1 > 9 ? (x-1+55).chr : (x-1)},#{y-1}"
found += 1;\$visits["#{y},#{x}"] = true
end
#vertical or horizontal
m_solver([x,y-1],found) if y-1 >= 1  and \$map[y-1][x] == '@' and
\$visits["#{y-1},#{x}"] == nil
m_solver([x,y+1],found) if y+1 <= 10 and \$map[y+1][x] == '@' and
\$visits["#{y+1},#{x}"] == nil
m_solver([x-1,y],found) if x-1 >= 1  and \$map[y][x-1] == '@' and
\$visits["#{y},#{x-1}"] == nil
m_solver([x+1,y],found) if x+1 <= 20 and \$map[y][x+1] == '@' and
\$visits["#{y},#{x+1}"] == nil
#diagonal
m_solver([x-1,y-1],found) if y-1 >= 1  and x-1 >= 1  and
\$map[y-1][x-1] == '@' and \$visits["#{y-1},#{x-1}"] == nil
m_solver([x-1,y+1],found) if y+1 <= 10 and x-1 >= 1  and
\$map[y+1][x-1] == '@' and \$visits["#{y+1},#{x-1}"] == nil
m_solver([x+1,y-1],found) if x+1 <= 20 and y-1 >= 1  and
\$map[y-1][x+1] == '@' and \$visits["#{y-1},#{x+1}"] == nil
m_solver([x+1,y+1],found) if x+1 <= 20 and y+1 <= 10 and
\$map[y+1][x+1] == '@' and \$visits["#{y+1},#{x+1}"] == nil
end
#worst case 198 lookups
m_solver(seed,0)

--
Posted via http://www.ruby-forum.com/.

```