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Explore Your Deductive Logic—Sudoku

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STEP 22 Continued

        Next k

        cantbelist =​ snapshotc

        ‘ build S2

Cells(i, j) =​ Right(putnumberpresent(i, j), 1)

        sbox(i, j) =​ Cells(i, j)

        Call fillemptycells

        For k =​ 1 To 9

          For l =​ 1 To 9

            s2(k, l) =​ Cells(k, l)

          Next l

        Next k

        ‘ restore snapshot

        For k =​ 1 To 9

          For l =​ 1 To 9

            Cells(k, l) =​ snapshot(k, l)

            sbox(k, l) =​ snapshot(k, l)

          Next l

          Next k

          cantbelist =​ snapshotc

          ‘compare s1 and s2

         

         

For k =​ 1 To 9

  For l =​ 1 To 9

        If s1(k, l) <> snapshot(k, l) And s2(k, l) =​ s1(k, l) Then

          Cells(k, l) =​ s1(k, l)

          sbox(k, l) =​ s1(k, l)

          snapshot(k, l) =​ s1(k, l)

        End If

      Next l

    Next k

    Call RefreshCantbelist

  End If

  Next j

Next i

We also need these functions that are called in the code.

Sub fillemptycells()

‘first check all cells -​ if 8 numbers in cantbelist, then we know the number

  For i =​ 1 To 9

    For j =​ 1 To 9

    If sbox(i, j) =​ ““ Then

      whatisthisnumber =​ 0

      For k =​ 1 To 9

      If cantbelist(i, j, k) > 0 Then

        howmanycantbe =​ k

        whatisthisnumber =​ whatisthisnumber +​ cantbelist(i, j, k)

      End If

    Next k

    If howmanycantbe =​ 8 Then