Count the number of nodes in a given binary tree

Objective: Given a binary tree, write an algorithm to count all the nodes in the tree.



  • Do postorder traversal.
  • If the root is null return 0. (base case all well for the recursion)
  • if the root is not null then make a recursive call to the left child and right child and add the result of these with 1 ( 1 for counting the root) and return.



Number of nodes in the given binary tree: 5

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