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Beginner’s Guide to Code Algorithms

54

STEP 14 continued

  For i =​ 1 To 9

    For j =​ 1 To 9

      putnumberpresent(i, j) =​ ““

    Next j

  Next i

  For i =​ 1 To 9

    ColumnCount =​ 0

    putnumberpresent(1, i) =​ ““

    lastcorner =​ ““

    For j =​ 1 To 9

      If sbox(j, i) =​ ““ Then

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

          lastcorner =​ lastcorner & j

          putnumberpresent(j, i) =​ lastcorner

          ColumnCount =​ ColumnCount +​ 1

        End If

      End If

    Next j

    If ColumnCount =​ 2 Then

    Else

      putnumberpresent(1, i) =​ “*”

    End If

  Next i

:

:

STEP 15

The second step is to scan the putnumberpresent array to identify the other two corners.

Once identified, all cells in the same two rows that the corners are in get the

candidate number (putnumber) in each of their cantbelist (remember the array that

stores what the cell cannot be?) except for the corners of the rectangle.

:

:

  For i =​ 1 To 9

    For j =​ 1 To 9

      If putnumberpresent(1, j) <> “*” And sbox(i, j) =​ ““ And

        putnumberpresent(i, j) <> ““ Then

        For k =​ j To 9

          If putnumberpresent(i, k) =​ putnumberpresent(i, j) And k <> j And

            Len(putnumberpresent(i, j)) =​ 2 And putnumberpresent(1, k) <>

“*” Then

              ‘column j,k and rows stored in putnumber are the rectangle

              ‘all cells in the rows of the rectangle except the corners,

              ‘should have putnumber in cantbelist

              For kk =​ 1 To 9

                If kk =​ j Or kk =​ k Then

                Else

                  Call addtocantbelist(putnumber, Mid(putnumberpresent(i, j), 1,

1), kk)