if (ARGV.length != 4)
    puts 'Usage: ruby comp24.rb <num1> <num2> <num3> <num4>'
    exit
end

input = ARGV.map {|s| s.to_f }
puts "Number List: #{input.inspect}"

#now start...
results=[]
lists = input.permutation(4).to_a

def for24(list,results)
    ops=['+','-','*','/']
    ops.each do |op|
        exp1="(#{list[0]}#{op}#{list[1]})"
        if(list.length == 2)
            results << exp1 if eval(exp1)==24
        else
            for24([exp1].concat(list[2,4]),results) if (0..24).to_a.include?(eval(exp1))
            if list.length == 3
                exp2="(#{list[1]}#{op}#{list[2]})"
                for24([list[0],exp2],results) if (0..24).to_a.include?(eval(exp2))
            end
        end
    end
end

lists.each do |list|
    for24(list,results)
end
#compute end....
#puts results.inspect

if (results.length == 0)
    puts "No solution!"
else
    puts "Solutions:"
    results.sort.uniq.each {|r| puts r.gsub(/\.0/,'')[1..-2]}
end