For the current node, consider all of its unvisited neighbors and calculate their tentative distances.

It also has a variable called N whose value is the current node of interest.

Step-2: Put that left child in the list of visited nodes and make it your current node in consideration.

Step-4: Make that right child as your current node in consideration.

Step-5: Check for the threaded node and if its there make it your current node.

Otherwise, if the viewing location V is in front of the current node:

Otherwise, if the viewing location V is behind the current node:

Otherwise, the viewing location V must be exactly on the plane associated with the current node.

For example, in A* search the evaluation function (where is the current node) is:

If that child is a leaf, insert the value into current node and finish.