docs: add visual for each AVL rotation

2 files changed, 43 insertions, 1 deletions

diff --git a/src/03/02/README.md b/src/03/02/README.md
index eebaa47..f60b1ec 100644
--- a/src/03/02/README.md
+++ b/src/03/02/README.md
@@ -1,4 +1,46 @@
 Illustrate that via AVL single rotation, any binary search tree T1 can be
 transformed into another search tree T2 (with the same items).
 
+Left rotation:
+
+```plaintext
+  (10)                  (20)
+    \                  /    \
+    (20)      ->    (10)    (30)
+      \
+      (30)
+```
+
+Right rotation:
+
+```plaintext
+     (30)            (20)
+     /              /   \
+   (20)     -->   (10)  (30)
+   /
+(10)
+```
+
+Left-Right rotation:
+
+```plaintext
+   (30)         (20)
+   /           /    \
+(10)     -> (10)    (30)
+   \
+   (20)
+```
+
+Right-Left rotation:
+
+```plaintext
+(10)             (20)
+    \            /  \
+    (30)  --> (10)  (30)
+   /
+(20)
+```
+
 Give an algorithm to perform this transformation using O(N log N) rotation on average.
+
+See `./../avl_tree.c`.
diff --git a/src/03/avl_tree_test.c b/src/03/avl_tree_test.c
index d0c675e..2c375cc 100644
--- a/src/03/avl_tree_test.c
+++ b/src/03/avl_tree_test.c
@@ -94,7 +94,7 @@ Ensure(insert_performs_a_right_left_rotation) {
     \            /  \
     (30)  --> (10)  (30)
    /
- (20)
+(20)
 */
   AVLTree *tree = avl_tree_initialize(10);
   tree = avl_tree_insert(tree, 30);