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Beginner’s Guide to Code Algorithms

58

STEP 18

The first step is to identify the corners of the polyomino and store them in an

array. This array is called putnumberpresent below. The entire row is scanned for

a candidate number (putnumber) and if the column contains exactly two cells that

could be a home for this number, this column is remembered along with the two rows

that could potentially be the two vertices of the polyomino.

‘*** algorithm to detect a golden polyomino

‘ Check each column and build putnumberpresent

For putnumber =​ 1 To 9

  For i =​ 1 To 9

    PCol(i) =​ ““

  Next i

  ColCount =​ 0

  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

      ColCount =​ ColCount +​ 1

      PCol(ColCount) =​ i

    Else

      putnumberpresent(1, i) =​ “*”

    End If

    Next i

:

:

STEP 19

The second step is to scan the putnumberpresent array to get them in an array of

rows, count the number of unique rows and the nodes.

:

  ‘* collecting all the row numbers in putnumberpresent

  nodecount =​ 0

  RowCount =​ 0

  For i =​ 1 To 9

    PRow(i) =​ ““

  Next i

  For i =​ 1 To 9