RUT

11222333-9

Ruby 1.8: ([*0..9]+%w{K 0})[11-rut.reverse.chars.each_with_index.inject(0){|a,(n,i)|a+n.to_i*(i%6+2)}%11] Ruby 1.8: ([*0..9]+%w{K 0})[11-rut.reverse.chars.inject([0,0]){|(i,a),n|[i+1,a+n.to_i*(i%6+2)]}[1]%11] Ruby 1.9: [*0..9,'K',0][11-rut.reverse.chars.each_with_index.inject(0){|a,(n,i)|a+n.to_i*(i%6+2)}%11] Ruby 1.9: [*0..9,'K',0][11-rut.reverse.chars.inject([0,0]){|(i,a),n|[i+1,a+n.to_i*(i%6+2)]}[1]%11]