4张扑克牌24点Ruby算法

4张任意的扑克牌，用+,-,*,/,(,) 计算总合等于24的方法。
缺点：没有过滤重复的算法，比如
24=(4+(10+(11-1)))和24=(4+(-1)+(10+11))原本是一样的。

#
# count 4 random numbers(1-13) to 24 by using +,-,*,/,(,)
#
#
require 'mathn' 

beginTime = Time.now
$opers = ['+','-','*','/']

def count24(total,data,str)
	
	lack = getSymmetry(str)
	lackNum = lack.abs
	count = 0
	
	cmd = ""
	
	if data.size>2 
		data_backup = data.clone	
		i = 0
		data_backup.each{ |number|			
			data = data_backup.clone
			data.delete_at(i)
			i +=1
			$opers.each{ |op|
				 if op=='+'
					cmd = str+"(" + number.to_s + "+"
					count24(total-number.to_i,data,cmd)
				 elsif op=='-'
				    cmd = str+"(-" + number.to_s + ")+"
					count24(total+number.to_i,data,cmd)
				 elsif op=='*'
				    cmd = str+number.to_s + "*("						
					count24(total.to_f/number.to_i,data,cmd)					
				 elsif op=='*'
				 	cmd = str+"(1\/" + number.to_s + ")*("
					count24(total*number.to_i,data,cmd)	
				 end
			}			
		}		
	elsif data.size==2	  
		n1 = data.at(0).to_i
		n2 = data.at(1).to_i		
		ok = false
		if total==n1 + n2
			cmd = str+"(" + n1.to_s + "+" + n2.to_s + ")"
			ok = true
		elsif total==n1*n2
			cmd = str+n1.to_s + "*" + n2.to_s
			ok = true
		end
		
		if !ok && n1>n2
			if n1-n2 == total
				cmd = str+"(" + n1.to_s + "-"+n2.to_s + ")"
				ok = true
			elsif n1.to_f/n2==total.to_f
				cmd = str+n1.to_s+ "/"+n2.to_s
				ok = true
			end
		elsif !ok
			if n2-n1 == total
				cmd = str+ "(" + n2.to_s + "-" + n1.to_s + ")"
				ok = true
			elsif n2.to_f/n1 ==total.to_f
				cmd = str+n2.to_s+"/"+n1.to_s
				ok = true
			end
		end		
		(if lack<0 
				lackNum.downto(1){cmd ="("+cmd}
		elsif lack>0
				lackNum.downto(1){cmd +=")"}
		end
		puts "24="+cmd) if ok		
	end	
end

def getSymmetry(str)
	n_left = 0
	n_right=0
	return 0 if str==nil || str.length==0	
	for i in 0...str.length
		if str[i,1]=='(' 
			n_left+=1
		elsif str[i,1]==')' 
			n_right+=1
		end
	end
	return n_left-n_right
end


data = Array.[]();


while data.length<4
	rn = rand(13)
	data << (rn==0?13:rn)
end


data.each{|i| print i,","}
print "\n"
puts "---------------------"
count24(24,data,"")

puts "---------------------"
puts " "+((Time.now.to_i-beginTime.to_i)/1000).to_s + " s"