オフラインリアルタイムどう書く#28 十字の壁がそそり立つ世界の中を君は螺旋状に歩く Ruby解答

spriwa.rb

#!/usr/bin/ruby
# http://nabetani.sakura.ne.jp/hena/ord28spirwa/

def parse(input)
    wall, day = input.split(":")
    n, e, s, w = wall.split(",")
    rs = [0,0]
    1.upto(n.to_i) { |y| rs << [0, y] }
    1.upto(e.to_i) { |x| rs << [x, 0] }
    1.upto(s.to_i) { |y| rs << [0, -y] }
    1.upto(w.to_i) { |x| rs << [-x, 0] }
    return rs, day
end

def check(wall, n, e, s, w)
    if ([e,w,n] - wall).empty?
        return s, "S"
    elsif ([n,e,s] - wall).empty?
        return w, "W"
    elsif ([e,s,w] - wall).empty?
        return n, "N"
    elsif ([n,s,w] - wall).empty?
        return e, "E"
    elsif ([s,w] - wall).empty?
        return e, "E"
    elsif ([n,w] - wall).empty?
        return s, "S"
    elsif ([n,e] - wall).empty?
        return w, "W"
    elsif ([e,s] - wall).empty?
        return n, "N"
    elsif wall.include?(n)
        return w, "W"
    elsif wall.include?(e)
        return n, "N"
    elsif wall.include?(s)
        return e, "E"
    elsif wall.include?(w)
        return s, "S"
    end
    return nill
end

def walk(wall, posi)
    x, y = posi[0], posi[1]
    n, e, s, w = [x, y+1], [x+1, y], [x, y-1], [x-1, y]
    nxt, ch = check(wall, n, e, s, w)
    wall << nxt
    return wall, nxt, ch
end

def solve(wall, day)
    posi = [1, 1]
    wall << posi
    ch = ""
    0.upto(day) {|d|
        wall, posi, ch = walk(wall, posi)
    }
    return ch
end

DATA.each{|line|
    num, input, expected = line.split( /\s+/ )
    
    wall, day = parse(input)
    actual = solve(wall, day.to_i)
    
    error = (actual == expected) ? "" : " ** expected is : #{expected} **"
    puts "%s -> %s %s" % [input, actual, error]
}
__END__
#0 2,3,5,4:85 S
#1 1,2,3,4:1 E
#2 1,2,3,4:2 S