Other Doug's Spiral #1

import sys

init_table = lambda ncols, nrows: [ [ None ] * ncols for i in xrange(nrows) ]

def iter_spiral(ncols, nrows):

    row, col = 0, 0

    # RED_FLAG: this is a HACK so that enumerate can be used as the
    #           counter and so we can skip the initial '0' value.
    #           Bad Doug! (not Hellman... the other one)
    yield row, col

    rowstart, rowstop = 0, nrows
    colstart, colstop = 0, ncols

    while rowstart < rowstop and colstart < colstop:
        for col in xrange(colstart, colstop):
            yield row, col

        rowstart += 1
        for row in xrange(rowstart, rowstop):
            yield row, col

        colstop -= 1
        for col in xrange(colstop-1, colstart-1, -1):
            yield row, col

        rowstop -= 1
        for row in xrange(rowstop-1, rowstart-1, -1):
            yield row, col

        colstart += 1


def spiral(ncols, nrows):

    ## Initialize an empty table
    table = init_table(ncols, nrows)

    ## Fill it in with values
    for val, (row, col) in enumerate(iter_spiral(ncols, nrows)):
        table[row][col] = val

    ## Print it out
    for row in table:
        for cell in row:
            print "%4d" % cell,
        print


spiral(*[int(v) for v in sys.argv[1:3]])