[LeetCode 145] Binary Tree Postorder Traversal

Given a binary tree, return the postorder traversal of its nodes' values.

For example: Given binary tree {1,#,2,3},

1
 \
  2
 /
3

return [3,2,1].

Note: Recursive solution is trivial, could you do it iteratively?

Diffculty
Hard

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[LeetCode ] Binary Tree Inorder Traversal Medium

Analysis