#96
Beauty is Symmetry
| Difficulty: | Easy |
| Topics: | trees |
Let us define a binary tree as "symmetric"
if the left half of the tree is
the mirror image of the right half of the tree.
Write a predicate to determine whether or not
a given binary tree is symmetric.
(see To Tree, or not to Tree for a reminder on
the tree representation we're using).
 | (= (__ '(:a (:b nil nil) (:b nil nil))) true) |
| (= (__ '(:a (:b nil nil) nil)) false) |
| (= (__ '(:a (:b nil nil) (:c nil nil))) false) |
| (= (__ [1 [2 nil [3 [4 [5 nil nil] [6 nil nil]] nil]]
[2 [3 nil [4 [6 nil nil] [5 nil nil]]] nil]])
true) |
| (= (__ [1 [2 nil [3 [4 [5 nil nil] [6 nil nil]] nil]]
[2 [3 nil [4 [5 nil nil] [6 nil nil]]] nil]])
false) |
| (= (__ [1 [2 nil [3 [4 [5 nil nil] [6 nil nil]] nil]]
[2 [3 nil [4 [6 nil nil] nil]] nil]])
false) |