Given two binary trees, write a function to check if they are equal or not.Two binary trees are considered equal if they are structurally identical and the nodes have the same value.

 

1 public boolean isSameTree(TreeNode p, TreeNode q) {2     if(p == null && q == null) return true;3     if(p == null || q == null) return false;4     if(p.val == q.val)5         return isSameTree(p.left, q.left) && isSameTree(p.right, q.right);6     return false;7 }