Palindromes

input.txt

68
oyncbgymhkrgfoosnxrlzmbxxdvyfclg
zqcolemtoatzmvypy
matebobomacbmmegcgbtu
ermcvdvpmyfmrumgywffaguyauuchqpuuhdayewfaq
ynhehazomiqkxqiajevzmxykvnjrxyttowrxakaymkwm
cteonyxcelmaohxgqpslmbzq
djfohodetjbngtfqxjrbjhxdvdngvnenqr
kmntddnpyognls
mjgvquobosirhpoeaqigczyerafadhiiqmkgfadudwlssdrns
qnnjeccqe
mbbqpwrmnzpbwebrimbbmhjnzkwijbhbqbrmkewmr
brtevyjxgrtbityqbksvjnvpbxnwqhnpasniwhtvqkaeq
oalxafblxbllirnlffxicewxayhiumncudqxxpqzttzaalwj
qptferpftufoervlcmz
diylyebqqniudbmnuylfmbewjwjyfjiuiju
omb
awngganw
ukftkdodwtddwhtsetsodecfuhcdbb
dvysjmgxuvncjonauhrkwafkvsdgdqyvfecs
iwifuduokejdenntarjtatktimomoiwrmiomffpjijpfo
mudzueajvzkfslvi
pcakdjjkdrqputgxuvetnsmeadqlvvo
yytqktfbrtkxbftaaxrq
nnspeyhcvbyyhahwsnwyegacopmpphvpbpmosgsns
ikjlaz
vnswwsvlnkwvlwhkyhvtythh
nlufazeoqpjlnujwjcxfoiswlqxwzxxqstokvln
gmlquegdxeyxmhspomoyhadwnijuzbxshkehbfv
hzbhrxfemhbibhfbrewenibfmbnbbzbbefw
rogqwidkeqmgrmcbwcbfyf
hprjhjxpxgglubtybuhjlgthcfbfawcgjtbygwgtdrdah
hgcpdzlenzzbvezqwavypbzpuluhvcbelrpvwvvqyzugelnuabr
aqywmngwgipgiqraqqwaqgrmyivvrpginwnrnaq
dmmdzjjkzk
ygovcdifiilkpdanj
ypawpwhnjxdrsvaibpiuoqdpgivounwixgpdcwgfpshi
iqpqlqqixpl
rierviiynmfaonkabbwtvokuyiphdbqmajqwzeggbmcu
dlpfgabkwhpsryzkwshicov
pzchwvopwxxgnmwfkavh
afxwxaawafyy
bcengudfrizahwypxdzrjfdtmsbwwowzh
qzapobigtiizkdzecifevtzzggdpcuovokmmwhzojet
grzurjavplptgfntbblskgcpaaysmzejiyatynya
broquzlbdmbtunannuqnj
liliagpalaadzzlgdp
etelteetqlzuuetqez
tyqqddnztrxlfqxwjkosxxfomxax
tmecjmihatku
jzojuzenjwhejfkjojtkaxjuieqrjlsbvbfuaroqkjltma
kskcjnjxklkiukrkqecuxenwgyklwkqiksygk
bkhyykyfniekweefqykixunoehjovujqfkvkfxjbj
icblnxwgbcmrkdjsvbpwxwvwhsnwpgnbspilghfu
oaluufelamwwsuefullaamsmzmzo
akpzifvrwtkhoijqzpmrckkfrklznwzzgvvoe
vqngjawpblaoflsietmxj
okgmrvghvfbjgpvqbtvfgdqncxknyinrybfsafbxsmupss
qitzdsqonrqadouruyr
iejfkmphtmollzmjedyusgchmjdyxxcwngwqxwwzbfu
dyyapadpp
auhpoxgtwdkiiifeubmbzv
hpgeppvvggerprg
unnornlpcayekapknbefbnnrukqonqbklacqfbaqny
wuqugipzcxrohdrgaphz
nttivynodletqbsxvxjdzpwty
yhhoigzdzpaiycvosyelenvvynsealpcrpprdvyyvev
ejqbgngktitiqcjqbykgbqigxbxityecnt
kmlalyqevfftxsjwxufteychuscbwnptuupq

output.txt

-1
-1
abbcegmmotuutommgecbba
aacdeffghmmpqruuuvwyyyywvuuurqpmmhgffedcaa
aaehijkkmmnoqrtvwxxyyzzyyxxwvtrqonmmkkjiheaa
-1
bddefghjjnnoqrtvxxvtrqonnjjhgfeddb
-1
-1
cenqjjqnec
ehijkmmmnpqrrwwzbbbbbbbbbbbbbbbbbbzwwrrqpnmmmkjihe
abbehijknnpqqrsttvvwxyggyxwvvttsrqqpnnkjihebba
-1
-1
defiijjlmnquuwyybbbbbbyywuuqnmljjiifed
-1
agnwwnga
bcdddefhkosttuwwuttsokhfedddcb
-1
adeffiiijjkmmnprttuwoooooooooowuttrpnmmkjjiiiffeda
-1
-1
abfkqrttxyyxttrqkfba
abceghhmnnopppvwyyssssssssssyywvppponnmhhgecba
-1
hhklnstvvwwyywwvvtsnlkhh
-1
-1
bbbbbeeffhhimnrwzxxzwrnmihhffeebbbbb
-1
abbcdfgggjjlprttuwxyhhhhhhhhhhyxwuttrpljjgggfdcbba
abbceeghllnppqruuvvvwyzzzddzzzywvvvuurqppnllhgeecbba
aaiimnnpqqqrrvwwyggggggggggywwvrrqqqpnnmiiaa
djkmzzmkjd
-1
-1
ilpqqxxqqpli
-1
-1
-1
aafwxyyxwfaa
-1
-1
-1
-1
aadgillpzzplligdaa
eeelqttuzzuttqleee
-1
-1
-1
cegijkkkkklnqsuwxyrryxwusqnlkkkkkjigec
beeffhijjkkknoquvxyywwyyxvuqonkkkjjihffeeb
-1
aaefllmmosuuwzzwuusommllfeaa
-1
-1
-1
-1
-1
adyppppppyda
-1
eggpprvhhvrppgge
aabbcefkklnnnnopqqruyyurqqponnnnlkkfecbbaa
-1
-1
acdeehilnopprsvvvyyyzggzyyyvvvsrpponliheedca
bbceggiijknqqttxyyxttqqnkjiiggecbb
-1

palindrome.rb

=begin
Given a file name input.txt with the following structure:

The first line is a positive number that indicates the number of lines in the file.
Each of these lines represents a string

Write a program that determines if a palindrome can be generated by rearranging the letters
in the string and write the output in a new text file called output.txt with the next format:

If the word cannot be rearranged to form a palindrome, write -1 otherwise generate a palindrome
using the letters in the string. If there is more than one palindrome that can be generated, only 
write one
=end

NOT_A_PALINDROME = "-1"

def get_palindrome 
  file = File.new "input.txt", "r"
  output = File.new "output.txt", "w"
  entries = file.gets.to_i      
  entries.times do 
    word_hash = Hash.new(0)
    line = file.gets.chars.sort.join
    line.each_char {|element| word_hash[element] += 1} 
    word_hash.delete "\n"
    output.puts is_palindrome?(word_hash) ? generate_palindrome(word_hash) : NOT_A_PALINDROME
  end       
  output.close
  file.close
end

def generate_palindrome hash
  palindrome = ""
  palindrome_center = ""
  hash.each_key do |item|
    value = hash[item].to_i      
    if value.even?         
      palindrome << item.to_str * (value/2)          
    else
      palindrome_center << item.to_str * value
    end                   
  end
  palindrome = palindrome << palindrome_center << palindrome.reverse
end

def is_palindrome? value
  counter = 0
  value.each_key {|index| counter += 1 unless value[index].even?}  
  counter <= 1
end

get_palindrome