Check If Two Trees Are Mirror

Now at nodes pointing to 2, all three conditions return true , therefore we can return true from this function and remove it from the recursion stack. Then at node 1, two conditions are true, therefore we call the right child of n1 and n2 to check the third condition. At nodes pointing to 2, two out of three conditions return true, so we will proceed further and check the third condition.

Perform iterative inorder traversal of one tree and iterative reverse inorder traversal of the other tree in parallel. We have discussed a recursive solution to check if two trees are mirror. In this post iterative solution is discussed.

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Part 2 of 2:Examining the Mirror

Check if two Trees are Mirror Images or not Write a C Program to Check if two Trees are Mirror Images or not. Here’s simple Program to Check if two binary trees are mirror image of each other or not in C Programming Language. Write a C Program to Check if two Trees are Mirror Images or not.

Consider the extreme measure of breaking the glass. If it’s a regular mirror, it will shatter and you’ll see the mirror’s backing or a solid wall. If it’s a two-way mirror, you’ll see the room behind the mirror. You should probably only consider this option if you feel threatened or are in danger. Breaking the glass will cause damage and create a safety hazard.

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The left subtree of the root node of the first tree is the same as the right subtree of the root node of the second tree and vice-e-versa. See the example, both the trees are the mirror of each other. As you can see above, except root node, the left child will become right and vice versa. This is the meaning of mirror of binary tree. The problem is to check whether the two binary trees are mirrors of each other or not.

The above conditions are checked recursively for the whole tree. From the above image we can arrive at below points that return true. If you can see in the above image, both the trees structure are mirror to each other. Left subtree of root of ‘a’ and right subtree root of ‘b’ are mirror.

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We will recursively call the right child of the nodes. Again that function will be added to our recursive stack. We need to write a recursive function isSymmetrical() that takes two trees as argument and returns true if trees are Symmetrical and false if trees are not Symmetrical. The isSymmetrical() function recursively checks two roots and subtrees under the root.

In the parent function where n1 and n2 point to 3, only two out of three conditions return true, therefore we will return the value false. In its parent function where n1 and n2 points to 1, again only two out of three conditions return true, therefore we will return false. Similar to step 4, n1 and n2 point to NULL, therefore we will again return true and the function will be removed from our recursion stack.

Program to check if two trees are mirror in Python

Node in a tree data structure, stores the actual data of that particular element and link to next element in hierarchical structure. We can’t have the entire tree in memory, so it’s not ideal to use recursion. Let’s assume, for simplicity’s sake, that we can only hold a maximum of two nodes in memory. In this tutorial, we will learn how to check if two trees are mirror or not in Python. If any of the two values are null, then the tree does not fit in the criteria to be called a mirror image.

A mirror image of a binary tree is another binary tree with left and right children of all non-leaf nodes of the given binary tree are interchanged. As they are equal, we again check for the left subtrees and add the function to our recursion stack. Given a 2 binary trees root nodes, check if the structure is mirror to each other. Two trees are said to be mirrors of each other when their structures are mirror images of each other.

Algorithm to check if two trees are mirror

C++ program to check if two trees are mirror or not. And, recursively, call the right subtree of tree 1 and left subtree of tree 2. Initially we have variables n1 and n2 pointing to the roots of both trees. This function is inside our recursion stack as well. Left subtree of this node is identical to the left subtree of the corresponding node. Below are the images that show the given Binary Tree & mirror image of a given binary tree.

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Check if two binary trees are Mirror of each other

There are cases in which the data is perfectly mirrored, and cases in which it isn’t. Blank data interlaced with non-blank data is considered “acceptable”, unless otherwise specified. We know n, the total number of levels in our tree. Connect and share knowledge within a single location that is structured and easy to search. This problem can be easily solved using the recursion, however, we will also demonstrate how it can be solved using the iterative method. This article is contributed by Ayush Jauhari.

You are required to complete the body of areMirror function. The function is expected to check if the two trees passed to it are mirror images of each other in shape . So just do inorder traversal on the first tree and a reverse inorder traversal on another and check if all the elements are the same. I would just iterate over the tree with two loops, one for the left branch and one for the right for every node. That way you aren’t storing anything other than two node values and two loop counters in memory. If there is an odd number of nodes, then just skip it and move down the tree.