def letterconv(letter)
	larr = ["A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"]
	narr = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26]
	i = 0
	while i < larr.length
		if letter == larr[i]
			return narr[i]
		end
		i += 1
	end
end

def gen_key_string(key,istr)
	istr = istr.gsub(" ",'')
	key = key.gsub(" ",'')
	istr = istr.upcase
	key = key.upcase
	karr = key.split(//)
	nkarr = []
	p = 0
	while nkarr.length < istr.length
		p = 0
		while p < karr.length
			if nkarr.length == istr.length
				break
			else
				nkarr << karr[p]
				p += 1
			end
		end
	end
	return nkarr
end

def strconv(strarr)
	narr = []
	i = 0
	while i < strarr.length
		narr << letterconv(strarr[i])
		i += 1
	end
	return narr	
end

def stradd(strarr1,strarr2)
	i = 0
	narr = []
	while i < strarr1.length
		narr << strarr1[i] + strarr2[i]
		i += 1
	end
	return narr
end

def strsubt(strarr1,strarr2)
	i = 0
	narr = []
	while i < strarr1.length
		narr << strarr1[i].to_i - strarr2[i].to_i
		i += 1
	end
	return narr
end

def strshort(strarr)
	i = 0
	narr = []
	while i < strarr.length
		bit = strarr[i]
		if bit > 26
			bit = bit - 26
			narr << bit
		else
			narr << bit
		end
		i += 1
	end
	return narr
end

def strshort2(strarr)
	i = 0
	narr = []
	while i < strarr.length
		bit = strarr[i]
		if bit < 0
			narr << 26 + bit
		else
			narr << bit
		end
		i += 1
	end
	return narr
end

def numconv(num)
	larr = ["A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"]
	narr = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26]
	i = 0
	while i < narr.length
		if num == narr[i]
			return larr[i]
		end
		i += 1
	end
end

def strconv2(strarr)
	narr = []
	i = 0
	while i < strarr.length
		narr << numconv(strarr[i])
		i += 1
	end
	return narr	
end

def encrypt(str,key)
	osstr = str.upcase.gsub(" ","").split(//)
	narr = gen_key_string(key,str)
	nosstr =  strconv(osstr)
	nnarr = strconv(narr)
	narr3 = stradd(nosstr,nnarr)
	narr4 = strshort(narr3)
	narr5 = strconv2(narr4)
	return narr5.join()
end

def decrypt(encrypted_string,key)
	variable_arr = encrypted_string.upcase.gsub(" ","").split(//)
	print variable_arr
	puts
	variable_key = gen_key_string(key,encrypted_string)
	variable_arr = strconv(variable_arr)
	variable_key = strconv(variable_key)
	new_number_array = strsubt(variable_arr,variable_key)
	new_number_array = strshort2(new_number_array)
	output_array = strconv2(new_number_array)
	return output_array.join
end

ostr = "this is a complex string"

key = "hello world"

ostr2 = encrypt(ostr,key)
puts decrypt(ostr2,key)