Reverse binary tree

He said reverse binary tree is the binary tree left subtree right subtree call, if they have a child, then about exchange also recursive.

Therefore, the step of the binary tree is briefly reversed:

• 1. reverse the root of the left subtree (recursively reverse function)
• 2. Reverse the root of the right subtree (recursively reverse function)
• 3. The exchange left and right node of the root node.

Inverted binary tree illustrated example:
Initial:

Initial Binary Tree

After the reverse:

After the reversal binary tree

code show as below:

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

        TreeNode temp = root.left;
        root.left = root.right;
        root.right = temp;
        return root;
    }

Reproduced in: https: //www.jianshu.com/p/9b2390f35de6