[GeeksForGeeks] Write a program to delete a tree

Write a program to delete a tree.

Solution. 

To delete all tree nodes, we need to set all non-leaf nodes‘ children nodes to null. So for a given non-leaf node, 

set its left child node to null, then set its right child node to null, then set the reference of this node to null. 

This manifests a post order traversal of a given binary tree. 

 1 public class DeleteTree {
 2     public void deleteTree(TreeNode node) {
 3         if(node == null) {
 4             return;
 5         }
 6         deleteTree(node.left);
 7         deleteTree(node.right);
 8         node = null;
 9     }
10 }

Follow up question: Can you solve this problem without using recursion?

[GeeksForGeeks] Write a program to delete a tree

原文：http://www.cnblogs.com/lz87/p/7343087.html