PROBLEM DESCRIPTION
Given a Binary Tree. Check whether it is Symmetric or not, i.e. whether the binary tree is a Mirror image of itself or not.
SOLUTION
create helper method isSame(r1, r2)
compare r1 and r2 values.
Then recursively check isSame(r1.left, r2.right) && isSame(r1.right, r2.left)
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class GfG
{
public static boolean isSymmetric(Node root)
{
return isSame(root, root);
}
public static boolean isSame(Node r1, Node r2){
// If both nodes are null, they are symmetric (mirror images of each other).
if(r1 == null && r2 == null)
return true;
// If one of the nodes is null and the other is not, they are not symmetric.
if(r1 == null || r2 == null)
return false;
// If the data in the current nodes doesn't match, they are not symmetric.
if(r1.data != r2.data)
return false;
// Recursively check if the left subtree of r1 is the mirror of the right subtree of r2
// and the right subtree of r1 is the mirror of the left subtree of r2.
return isSame(r1.left, r2.right) && isSame(r1.right, r2.left);
}
}