Invert Binary Tree: A binary tree is a tree in which each node of the tree contains two children, i.e., left children and right children. Let us suppose we have given a binary tree, and the task is to invert the given binary tree. Inverting a Tree will create the mirror of it.

For Example:

Input:

Output:

Explanation: Inverting the given binary tree will flip all the nodes as a mirror image.

The approach used in the below program to solve this problem is as follows:

Inverting a binary tree is also known as the mirroring of the given tree, but to invert a binary tree, we will create a temporary node that will keep the nodes in each level and swap the left node as well as a right node.

Take input nodes of the binary Tree.
A function flipNode(node*root) takes the root node as input and helps to create the mirror of the node.
Swap the left node and right node.
A function invertBinaryTree(node*root) takes the root node and calls the flipNode(root) function to convert a binary tree in its invert form.

Example:

#include<iostream> using namespace std; 
struct treenode
{  
int data;  
treenode*left; 
 treenode*right;
 };  
struct treenode* createNode(int d)
{    
 struct treenode*root= new treenode;  
   root->data= d;     root->left= NULL;     root->right= NULL;     return root;   
  }  
void flipNodes(treenode*root)
{    
 if(root==NULL)
{        
 return;    
 }   
 treenode*temp= root->left;    root->left= root->right;    root->right= temp; 
} 
treenode*invertBinaryTree(treenode*root)
{    
 flipNodes(root);     return root; 
}  
int heightofTree(treenode*root)
{    
 if(root==NULL)
{      
   return 0;   
  }     
return max(heightofTree(root->left), heightofTree(root->right))+1;
 } 
 void givenlevel(treenode*root, int lev)
{  
   if(root==NULL)
{    
     return;  
   }    
 if(lev==1)
{         
cout<<root->data<<" ";    
 }    
 else if(lev>1)
{      
   givenlevel(root->left,lev-1);
         givenlevel(root->right,lev-1);
     } 
}
  void printLevelwise(treenode*root)
{   
  int height= heightofTree(root);
     int i;     for(i=1;i<=height;i++)
{       
  givenlevel(root,i); 
   }
 }  
int main()
{ 
struct treenode*root= NULL;
 root= createNode(4); 
root->left= createNode(2); 
root->right= createNode(7);
 root->left->right= createNode(3);
 root->left->left= createNode(1);
 root->right->left= createNode(6);
 root->right->right= createNode(9);
 printLevelwise(root); 
cout<<"After Inverting:"<<endl; invertBinaryTree(root);
 printLevelwise(root);  
return 0; }

Running the above code will generate the output as follows:

Output:

 4 2 7 1 3 6 9
 After Inverting:
 4 7 2 6 9 1 3

Invert Binary Tree in DAA