Check if two binary trees are equal

SameTree.java

public class SameTree{
 
   public boolean isSameTree(TreeNode p, TreeNode q) {
      
      if(p == null && q == null) return true;
      
      if(p == null || q == null) return false;
      
      if(p.val != q.val) return false;
      
      return isSameTree(p.left, q.left) && isSameTree(p.right, q.right);
  }
}