Finding a Key in aBinary Search Tree

• To recursively search for a target in a subtree (starting at root):

  • If the subtree is empty, return failure (NULL)
  • Otherwise:
    • If the target is < the key of the subtree root, recursively search the left subtree for the target and return the result value
    • Otherwise, if the target is > the key of the subtree root, recursively search the right subtree for the target and return the result value
    • Otherwise, the target must be == to the key of the subtree root; return the pointer to the subtree root

• The only recursion is tail recursion; an iterative solution is:

  • While subtree is not empty and the subtree key is != target
    • If target < subtree key, set subtree to left child
    • Otherwise, set subtree to right child
  • Return final subtree pointer

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