Complete the function in the editor below. It received parameter: a pointer to the root of a binary tree. It must print the values in the tree's postorder traversal as a single line of space-separated values.
Input Format
Our test code passes the root node of a binary tree to the function.
Constraints
Nodes in the tree
Output Format
Print the tree's postorder traversal as a single line of space-separated values.
Sample Input
1
\
2
\
5
/ \
3 6
\
4
Sample Output
4 3 6 5 2 1
Explanation
The postorder traversal is shown.