Check for identical binary trees

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We need to check that the given trees are identical or not.


We will check for each node in both the trees.

There will be three cases:

  • If the root of both trees is NULL this means trees are identical.
  • If one node is NULL and the other is not, this means trees are not identical.
  • If both node’s data is not equal then trees are not identical.
  • Now we will recursively traverse all the nodes and follow the above steps for every node.
using namespace std;

struct Node{ int data; Node* left; Node* right; Node(int data){ this->data = data; left = right = NULL; } };

bool isIdentical(Node *root1, Node *root2){ if(root1 == NULL && root2 == NULL) return true;

if((root1 &amp;&amp; !root2) || (!root1 &amp;&amp; root2)) return false;

if(root1-&gt;data != root2-&gt;data) return false;

return isIdentical(root1-&gt;left, root2-&gt;left) &amp;&amp; isIdentical(root1-&gt;right, root2-&gt;right);


int main() { /* 1 /
2 3 / \ /
4 5 6 7 / struct Node root = new Node(1); root->left = new Node(2); root->left->left = new Node(4); root->left->right = new Node(5); root->right = new Node(3); root->right->left = new Node(6); root->right->right = new Node(7); cout<<isIdentical(root, root);

return 0;


TC – O(N)

Check for identical binary trees