Upside Down Binary Tree in Java
An existing binary tree can be modified in a particular manner with the help of an upside-down binary tree structure. The original tree's nodes are modified in this transformation so that each node becomes a new root while the hierarchical relationships are maintained. Recursively traversing the tree from the root produces the leftmost node, which serves as the new root of the modified tree.
The reconfiguration occurs through the recursive traversal. The subtree's new root is the left child node of the original root node. The right child of the original root will become the right child of the new left child, and the original root's right child becomes the new root's right child.
Input:
Output:
Algorithm:
Step 1: To represent the nodes in the binary tree, define a TreeNode class.
Step 2: A value and references to its left child node and right child node are stored in every node.
Step 3: Continue with the transformation, starting from the original tree's root.
Step 4: Analyze base conditions in which both the left child node and the root are null.
Step 5: To reverse the tree nodes, rearrange the pointers.
Step 6: Uses recursion to perform the modifications.
Step 7: Reorganizes pointers to reverse the tree's structure.
Step 8: Offers a simple method to convert a binary tree into its reversed version while maintaining node values and relationships.
Filename: UpsideDownBT.java
class TreeNode
{
int value;
TreeNode left;
TreeNode right;
TreeNode(int value)
{
this.value = value;
}
}
public class UpsideDownBT // performing upside down method
{
public TreeNode upsideDownBinaryTree(TreeNode root)
{
if (root == null)
return null;
TreeNode prev = null;
TreeNode curr = root;
TreeNode next = null;
TreeNode temp = null;
while (curr != null)
{
next = curr.left;
curr.left = temp;
temp = curr.right;
curr.right = prev;
prev = curr;
curr = next;
}
return prev;
}
public TreeNode constructTree() // construction of the sample tree
{
TreeNode root = new TreeNode(29);
root.left = new TreeNode(20);
root.right = new TreeNode(77);
root.left.left = new TreeNode(93);
root.left.right = new TreeNode(29);
return root;
}
public void printTree(TreeNode root) // printing the binary tree using preorder traversal
{
if (root == null)
return;
System.out.println(root.value);
printTree(root.left);
printTree(root.right);
}
public static void main(String[] args)
{
UpsideDownBT solution = new UpsideDownBT();
TreeNode root = solution.constructTree();
System.out.println("The Original Tree of the Upside Down Binary Tree is: ");
solution.printTree(root);
TreeNode upsideDownRoot = solution.upsideDownBinaryTree(root);
System.out.println("\nUpside Down Tree:");
solution.printTree(upsideDownRoot);
}
}
Output:
The Original Tree of the Upside Down Binary Tree is:
29
20
93
29
77
Upside Down Tree:
93
29
20
77
29
Complexity:
The reversed transformation has a time complexity of exactly one visit to every node in the tree. The time complexity is O(n), where "n" is the number of nodes in the original tree due to every node being visited as soon as possible. As the depth of recursion could be the same as the number of nodes, in the worst-case situation of a skewed tree (e.g., related to a linked-like structure), the space complexity could reach O(n).
Applications:
Tree Operations and Traversal Modifications: Modifying the tree structure according to particular techniques for problem-solving makes some tree-based algorithms easier. Modifies the order in which nodes are traversed, possibly improving certain algorithms that depend on tree traversal.
Algorithm Design and Tree Modification: Tree modification can be useful for improving data representation and operations in some applications, consisting of parsers, compilers, and data processing.
Data Transformation: Provides a different tree representation that might be more practical or efficient for different responsibilities and provides a modified tree structure for specific manipulations that facilitates the creation of algorithms.
Conclusion:
In Java, an upside-down binary tree requires modifying node pointers to change the tree's structural order. The upside-down structure can be created by recursively traversing the left branch of the tree and rearranging the pointers. Returning the new root of the upside-down tree after traversing to the leftmost node and rearranging the structure using pointer updates. In specific conditions, this method can be helpful when the tree is represented upside-down binary tree.