I know the point of this article is not to give the fastest n-queens algorithm. But what the heck; here is an iterative backtracking solution. On my machine, this code finds all solutions for the 10x10 board in about 1.2 sec, while the code from the article takes just under 18 sec. Using CPy 2.6.5, just like the article. Have not tried PyPy. Output is essentially the same format, except that my generator spits out lists instead of tuples.

Yes, it's twice as long and harder to read. Improvements, anyone?

  def hit_last(p):
      x = p[-1]
      i = len(p)-1
      for j in range(i):
          y = p[j]
          if x == y or i - j == abs(x - y):
              return True
      return False

  def n_queen(n):
      p = [0]
      while True:  # Begin iter w/ board good, except maybe last Q
          full = len(p) == n
          hit = hit_last(p)
          if full or hit:  # Will we backtrack?
              if not hit:  # Found solution?
                  yield p
              while len(p) > 0 and p[-1] == n-1:
                  p.pop()
              if len(p) == 0:
                  return
              p[-1] += 1
          else:
              p.append(0)