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Explore Your Deductive Logic—Sudoku

51

STEP 12 continued

    Next k

    If sbox(j, i) =​ ““ And cantbelistcount(j, i) =​ 7 Then

      putnumberpresent(j, i) =​ ““

      For putnumber =​ 1 To 9

        If findincantbelist(putnumber, j, i) =​ 0 Then

          putnumberpresent(j, i) =​ putnumberpresent(j, i) & putnumber

        End If

      Next putnumber

    End If

    For k =​ 1 To i -​ 1

      If putnumberpresent(j, k) <> ““ And

        putnumberpresent(j, k) =​ putnumberpresent(j, i) Then

        For kk =​ 1 To k -​ 1

          Call addtocantbelist(Mid(putnumberpresent(j, k), 1, 1), j, kk)

          Call addtocantbelist(Mid(putnumberpresent(j, k), 2, 1), j, kk)

        Next kk

        For kk =​ k +​ 1 To i -​ 1

          Call addtocantbelist(Mid(putnumberpresent(j, k), 1, 1), j, kk)

          Call addtocantbelist(Mid(putnumberpresent(j, k), 2, 1), j, kk)

        Next kk

        For kk =​ i +​ 1 To 9

          Call addtocantbelist(Mid(putnumberpresent(j, k), 1, 1), j, kk)

          Call addtocantbelist(Mid(putnumberpresent(j, k), 2, 1), j, kk)

        Next kk

        Exit For

      End If

    Next k

    Next j

Next i

STEP 13

The final step is to do the same for each 3 by 3 grid. We do not need to create the

putnumberpresent row again, since we have already built it. But it is a good idea to

refresh this list each time the cantbelist is updated.

For i =​ 1 To 9 Step 3

  For j =​ 1 To 9 Step 3

    For k =​ 1 To 3

      n =​ Int((i -​ 1) /​ 3) * 3 +​ k

      For l =​ 1 To 3

        p =​ Int((j -​ 1) /​ 3) * 3 +​ l

        For ka =​ 1 To 3

          na =​ Int((i -​ 1) /​ 3) * 3 +​ ka

          For la =​ 1 To 3

            pa =​ Int((j -​ 1) /​ 3) * 3 +​ la

            If n <> na Or p <> pa Then

              If putnumberpresent(n, p) <> ““ And

                putnumberpresent(n, p) =​ putnumberpresent(na, pa) Then