' version 30-03-2017
' compile with: fbc -s console

Data "ABCD", "CABD", "ACDB", "DACB", "BCDA", "ACBD"
Data "ADCB", "CDAB", "DABC", "BCAD", "CADB", "CDBA"
Data "CBAD", "ABDC", "ADBC", "BDCA", "DCBA", "BACD"
Data "BADC", "BDAC", "CBDA", "DBCA", "DCAB"

' ------=< MAIN >=------

Dim As ULong total(3)  ' total(0 to 3)
Dim As ULong i, j, n = 24 \ 4   ' n! \ n
Dim As ULong total_val = (Asc("A") + Asc("B") + Asc("C") + Asc("D")) * n
Dim As String tmp

For i = 1 To 23
    Read tmp
    For j = 0 To 3
        total(j) += tmp[j]
    Next
Next

tmp = Space(4)
For i = 0 To 3
    tmp[i] = total_val - total(i)
Next

Print "The missing permutation is : "; tmp

' empty keyboard buffer
While Inkey <> "" : Wend
Print : Print "hit any key to end program"
Sleep
End