Invert Binary Tree

Problem Link

Invert a Binary Tree (opens in a new tab)

Problem Statement

• Here's a tree, and we need to reverse/invert the elements of the tree on each level
• Check how in each level, the nodes are changed across subtrees.

Algorithm

A main part about trees is recursions. We need to swap the elements of each node on each level.

• Base case: if the root is null, return null.
• Do a recursion for the left of root and right of root.
• Swap the left and right of root using a temporary variable.
• Return the root

Code

class Solution {
    public TreeNode invertTree(TreeNode root) {
        if (root==null){
            return null;
        }
        invertTree(root.left);
        invertTree(root.right);
        TreeNode tmp = root.left;
        root.left = root.right;
        root.right = tmp;
        return root;
    }
}