Determine if Two Trees are Identical

Problem Statement - link #

Given two binary trees, the task is to find if both of them are identical or not.

Your Task: Since this is a functional problem you don’t have to worry about input, you just have to complete the function isIdentical() that takes two roots as parameters and returns true or false. The printing is done by the driver code.

Expected Time Complexity: O(N)
Expected Auxiliary Space: O(height of the tree)

Examples #

Example 1:

Input:
    1       1
  /  \     /  \
 2    3   3    2
Output: No
Explanation: There are two trees both
having 3 nodes and 2 edges, but both
trees are not identical.

Example 2:

Input:
     1          1
   /   \      /   \
  2     3    2     3
Output: Yes
Explanation: There are two trees both
having 3 nodes and 2 edges, both trees
are identical having the root as 1,
left child of 1 is 2 and right child
of 1 is 3.

Constraints #

• 1 <= Number of nodes <= 10^5
• 1 <= Data of a node <= 10^5

Solutions #

class Solution
{
    public:
    //Function to check if two trees are identical.
    bool isIdentical(Node *r1, Node *r2)
    {
        //Your Code here
        if(r1 == NULL || r2 == NULL)  return(r1 == r2);
        return(r1 -> data == r2 -> data)
        && isIdentical(r1 -> left, r2 -> left)
        && isIdentical(r1 -> right, r2 -> right);
    }
};