Leetcode Problem 1973. Count Nodes Equal to Sum of Descendants

1973. Count Nodes Equal to Sum of Descendants

Leetcode Solutions

Recursive Postorder Traversal

  1. Define a recursive function dfs that takes a TreeNode as an argument and returns the sum of the values of its descendants.
  2. If the current node is null, return 0.
  3. Recursively call dfs on the left child and store the result in leftSum.
  4. Recursively call dfs on the right child and store the result in rightSum.
  5. Calculate the total sum by adding leftSum and rightSum.
  6. If the total sum equals the value of the current node, increment the count.
  7. Return the total sum plus the value of the current node to the parent call.
  8. Start the traversal by calling dfs on the root node.
  9. After the traversal, return the count of nodes that met the condition.
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Iterative Postorder Traversal using Stack

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