I try to solve this problem http://www.nattee.net/~dae/algo/prob/hw03b_tiling/problem.pdf
So I using divide and conquer method to solve it but when I execute my program I get
tile.rb:7: stack level too deep (SystemStackError)
And this is my code
def tile (x, y, bx, by, ex, ey)
mx = (bx+ex)/2
my = (by+ey)/2
if (by<=y && y<=my)
if (bx<=x && x<=mx) # top-left
puts "0 #{mx} #{my}"
elsif (mx+1<=x && x<=ex) # top-right
puts "1 #{mx} #{my}"
end
elsif (my+1<=y && y<=ey)
if (bx<=x && x<=mx) # bottom-left
puts "2 #{mx} #{my}"
elsif (mx+1<=x && x<=ex) # bottom-right
puts "3 #{mx} #{my}"
end
end
tile(x,y,bx,by,mx,my) #top-left
tile(x,y,mx+1,by,ey,my) #top-right
tile(x,y,bx,my+1,mx+1,ey) #bottom-left
tile(x,y,mx+1,my+1,ex,ey) #bottom-right
if ex-bx == 2 && ey-by == 2 then return end
end
temp = []
gets.chomp.strip.split(" ").each do |item|
temp << item.to_i
end
L = temp[0]
x = temp[1]
y = temp[2]
tile(x,y,0,0,L-1,L-1)
I can't find the cause.
There is no way out of your recursion - for every call to tile, it will make 4 more calls to tile. Recursion always needs a "relief valve" way out before the recursion call. Try moving your return up before the tile calls.
The return statement could stand to be written in more idiomatic ruby.
Try:
return if (ex-bx == 2 && ey-by == 2)
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