code: def triangles(creation_sequence):
      """
      Compute number of triangles in the threshold graph with the
      given creation sequence.
      """
      # shortcut algorithm that doesn't require computing number
      # of triangles at each node.
      cs = creation_sequence  # alias
      dr = cs.count("d")  # number of d's in sequence
      ntri = (
          dr * (dr - 1) * (dr - 2) / 6
      )  # number of triangles in clique of nd d's
      # now add dr choose 2 triangles for every 'i' in sequence where
      # dr is the number of d's to the right of the current i
      for i, typ in enumerate(cs):
          if typ == "i":
              ntri += dr * (dr - 1) / 2
          else:
              dr -= 1
      return ntri
  
imports: from math import sqrt
  import networkx
  from networkx.utils import py_random_state
label_desc: Use image node_id 12 for calling a global function with example usage: triangles(creation_sequence) and returns: ntri