Given two binary trees, determine if they are mirror trees.

Question: Given 2 binary trees, determine if they are mirror of each other

Input: 2 tree pointers are given. (Root pointer)
Output: TRUE

We can again apply the recursive sub-structure property of the tree here. The algorithm can be implemented as:-

#include<stdio.h>
#include<malloc.h>

struct binaryTreeNode{
	int data;
	struct binaryTreeNode * left;
	struct binaryTreeNode * right;
};

int areTreeMirrors(struct binaryTreeNode * root1, struct binaryTreeNode * root2)
{
	// Terminating condition
	if(root1 == NULL && root2 == NULL)
		return 1;
	
	//If one of them is NULL, then they are definitely not mirrors
	if(root1 == NULL || root2 == NULL)
		return 0;
	
	//If one of them is different, then also they are not mirrors
	if(root1 -> data != root2 -> data)
	{
		return 0;
	}
	else
	{
		// Compare the left and right nodes of the trees
		return (areTreeMirrors(root1 -> left, root2 -> right) && areTreeMirrors(root1 -> right, root2 -> left)); 
	}
}

Time Complexity:- O(n)
Space Complexity:- O(n) due to a recursive stack