Write a method named readTree that accepts a Scanner as a parameter representing a file of data for a binary tree of integers, reads that file and builds and returns the root of a tree constructed from the data in that file.
The tree has been stored in the file using a pre-order traversal with one line for each node.
Each line of input has a numeric code indicating the type of node, followed by the data in the node.
The format for each node is a code indicating the type of node (from the table below) followed by the data in the node.
Below the table is a data file stored in the above described format (and being read by a Scanner called input) and the tree referenced by variable tree that a call to readTree(input) would create.
| Code |
Node Type |
0 |
leaf node (no children) |
1 |
branch node with left child only |
2 |
branch node with right child only |
3 |
branch node with left and right children |
For example, given a Scanner named input that reads from the following input file:
3 7
1 9
0 5
3 8
2 4
0 9
0 6
The call of readTree(input) would return a TreeNode referring to the root of the following tree:
(7 (9 (5)) (8 (4 / (9)) (6)))
If the file is empty, return an empty (null) tree.
Remember that you are creating a tree based on the information in the file.
Assume that you are interacting with TreeNodes as defined below:
public class TreeNode {
public int data;
public TreeNode left;
public TreeNode right;
public TreeNode() { ... }
public TreeNode(int data) { ... }
public TreeNode(int data, TreeNode left, TreeNode right) { ... }
}
