Algorithms and Data Structures

  • Profound Academy

    • Status
      • 1
        Implementation
      • 2
        Bitwise operations
      • 3
        Prefix Sums
      • 4
        Sliding window / Two pointers
      • 5
        Modular Arithmetic
      • 6
        Number Theory
      • 7
        Binary Search
      • 8
        Basic Sorting
      • 9
        Greedy Algorithms
      • 10
        Basic Dynamic Programming
      • 11
        Recursion
      • 12
        Linked LIst
      • 13
        Queue & Stack
      • 14
        Binary tree + BST
      • 15
        Divide & Conquer + Advanced Sorting
      • 16
        Heap
      • 17
        Hashing
      • 18
        Graph Representation

  • Post-order traversal of a binary tree

    Post-order traversal of a tree is a recursive procedure, where you first the left subtree of a node, then visit its right subtree, and then the node itself:
    1. Visit the left subtree (node.left)
    1. Visit the right subtree (node.right)
    1. Visit the current node
    Given a binary tree, you are asked to perform a post-order traversal on it.

    Input

    The input contains space-separated integers representing the values in the nodes of the binary tree. The order of the values is given by traversing from the left to the right subtree every time. A value of 0 means that the node does not exist. It’s guaranteed that the input binary tree is valid.

    Output

    The program should print the values in the nodes of a binary tree when performing a post-order traversal. All the values should be separated by a space.

    Examples

    Input
    Output
    1 2 3 4 5 8 9 0 0 0 0 0 0 6 7 0 0 0 0
    8 9 4 5 2 6 7 3 1
    1 2 3 4 5 8 0 0 0 0 0 6 7 0 0 0 0
    8 4 5 2 6 7 3 1
    1 2 3 4 5 0 0 0 0 6 7 0 0 8 9 0 0 0 0
    4 5 2 6 8 9 7 3 1
    1 2 3 4 5 0 0 7 8 0 0 0 0 0 6 0 0
    4 7 8 5 2 6 3 1

    Explanation

    1. Example 1:
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    1. Example 2:
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    1. Example 3:
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    1. Example 4:
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    Constraints

    Time limit: 1 seconds

    Memory limit: 512 MB

    Output limit: 1 MB

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