# For @answ_hoa1, note that 2nd elem of 4th array is "-" and not "D"
# because elem[last] in 2nd array ("B") has been *used* before

my @answ_hoa1 = (
                  ["A","A","A","A"],
                  ["B","B","-","B"],
                  ["C","-","-","C"],
                  ["D","-","D","-"],
               );

my @answ_hoa2 = (
                 ["A","A","-"],
                 ["D","-","-"],
               );