title: Count Words Appear Exactly Two Times Array Words
signature: function count_words_appear_exactly_two_times_array_words(stri, n)
test_code: 
  
  -- SOLUTION CODE
  -- ============================================
  PLACEHOLDER_CODE_BODY
  
  -- TESTING CODE 
  -- ============================================
  function isCorrect(actual, expected)
      if type(expected) ~= type(actual) then
          return false
      end
      
      if type(expected) == 'table' then
          for k,v_expected in pairs(expected) do
              
              if actual[k] == nil then
                  return false
              end
              local v_actual = actual[k]
              if not isCorrect(v_actual, v_expected) then
                  return false
              end
              actual[k]=nil
          end
      
          if next(actual) then 
              return false
          end
          return true
      else
          return actual == expected
      end
  end
  
  function validateSolution(actual, expected)
      return isCorrect(actual,expected)
  end
  
  function driver(stri, n, expected)
      local exec_result;
      local status, error_msg = pcall(function () 
          exec_result=PLACEHOLDER_FN_NAME(stri, n) 
      end)
      if status then
          if validateSolution(exec_result,expected) then
              return "PASSED"
          end
          return "FAILED"
      else
          return string.format("ERROR=%s",string.gsub(error_msg,".*:[%d]+: ",""))
      end
  end
      
  function main()
      result = driver({"hate", "love", "peace", "love", "peace", "hate", "love", "peace", "love", "peace"}, 10, 1)
      print(string.format("TEST-0...%s",result))
  
      result = driver({"16", "946613197072", "532052", "42780833", "511552", "1241934", "4", "3444540", "47487223670074", "23753", "14158", "4", "95420017116714", "16", "0845", "689000748", "976403809728", "8922", "487784120896", "329", "611", "59101", "611", "2131059721", "53952148295020", "445948587", "3905249775372", "4683180907", "7169093", "01413852276627", "63", "5864", "40862536595", "2280304422294", "930028582", "05", "33447"}, 32, 3)
      print(string.format("TEST-1...%s",result))
  
      result = driver({"001000100000", "1010", "01011", "11", "011", "1010"}, 6, 1)
      print(string.format("TEST-2...%s",result))
  
      result = driver({"Om", "Om", "Shankar", "Tripathi", "Tom", "Jerry", "Jerry"}, 7, 2)
      print(string.format("TEST-3...%s",result))
  
      result = driver({"2", "644", "2", "42484637089", "81578664", "0778"}, 6, 1)
      print(string.format("TEST-4...%s",result))
  
      result = driver({"001000101", "011010", "1", "101010011", "011010", "01", "10111000101", "0", "1", "00101101", "0", "0"}, 12, 2)
      print(string.format("TEST-5...%s",result))
  
      result = driver({"kl", "p sH", "PwCPMPu", "tQoIgPpk", "wtsNP WjS", "kl ", "TXsFWgU", "kl", "AD", "NjjTyFGwNWZcB", "jpFQslbGbDI", "cEpGAgvpk", "EMaDkMOm", "YZuNZgfwDIjG", "k", "hJx jHmGpQYwQP", "CIETe", "RH", "Pj", "h", "DInR", "AEsqOvliQtz", "NwzHTALTt LS", "LwLR", "WvDCzlQF", "soJb", "WktoldCbWyTO", "pIdRJxY", "BmpWxjOwTXkjjL", "zmtCiQ", "g", "yBmDW", "QhaBZrQnOJaAJ", "u", "MGTwCKve", "UxYQrONag", "xsGSz", "dqNPTT", "U W", "ygJKvCEKDClby", "M", "yXJQHxjyDQDLkT", "oJmaREOEk YA", "zUwiwhSMdiC", "jYgZEktcdgLD", "fwyTAAW", "GENttdzeGY "}, 43, 1)
      print(string.format("TEST-6...%s",result))
  
      result = driver({"938", "074209", "0949093096", "218622476", "71692175", "0714", "81217924991", "74016430795374", "52213147", "338", "939", "798161500954", "90528060774015", "68715", "75810", "43450", "8017", "0193164", "5945740", "212", "4589289", "2912211026", "0", "49", "8230114", "0733435391403", "5429", "10070"}, 20, 0)
      print(string.format("TEST-7...%s",result))
  
      result = driver({"00", "0", "00", "0101111010100", "110"}, 4, 1)
      print(string.format("TEST-8...%s",result))
  
      result = driver({"g", "h", "ok", "h", "ok", "sqozuC", "ut", "ZwRcG", "ok", "MR", "jHrWyy", "qaJlrokgRHuZH", "LjPNzDUKszYmCq", "g", "ZGjLfMnyAGL", "kEZoSxOMEWSFpw", "IFtqNaDVnG", "iJoJXl", "vjrQMyWor", "FTEHZqbHGlmHph", "QeSdzm", "nPostKHkigyJt", "mOSekk"}, 15, 2)
      print(string.format("TEST-9...%s",result))
  
  end
  
  main()
source_py: def count_words_appear_exactly_two_times_array_words(stri, n):
      m = dict()
      for i in range(n):
          m[stri[i]] = (m.get(stri[i], 0) + 1)
      res = 0
      for i in m.values():
          if (i == 2):
              res += 1
      return res
source_cpp: int count_words_appear_exactly_two_times_array_words(vector<string> str, int n) {
    unordered_map < string, int > m;
    for ( int i = 0;
    i < n;
    i ++ ) m [ str [ i ] ] += 1;
    int res = 0;
    for ( auto it = m . begin ( );
    it != m . end ( );
    it ++ ) if ( ( it -> second == 2 ) ) res ++;
    return res;
  }