Bumblebee - Esther K.

part-1.py

@@ -4,17 +4,38 @@
 # the appropriate comment.
 
 # factorial
+def factorial(n):
+    if n < 0:
+        raise ValueError
 
+    if n == 0:
+        return 1
+
+    return factorial(n - 1) * n
 
 
 # reverse
+def reverse(text):
+    if text == "":
+        return ""
 
+    return reverse(text[1:]) + text[0]
 
 
 # bunny
+def bunny(count):
+    if count == 0:
+        return 0
 
+    return bunny(count - 1) + 2
 
 
 # is_nested_parens
+def is_nested_parens(parens):
+    if not parens:
+        return True
 
+    if parens[0] != "(" or parens[-1] != ")":
+        return False
 
+    return is_nested_parens(parens[1:-1])

part-2.py

@@ -4,13 +4,63 @@
 # the appropriate comment.
 
 # search
+# this implementation changes the list provided
+def search(array, query):
+    if not array:
+        return False
 
+    if array.pop() == query:
+        return True
+
+    return search(array, query)
+
+
+def search_preserve_array(array, query):
+    if not array:
+        return False
+
+    if array[0] == query:
+        return True
+
+    return search_preserve_array(array[1:], query)
 
 
 # is_palindrome
+def is_palindrome(text):
+    if not text:
+        return True
+
+    if text[0] != text[-1]:
+        return False
+
+    return is_palindrome(text[1:-1])
 
 
+# challenge attempt
+def is_palindrome_challenge(text):
+    return is_palindrome_challenge_helper(text, 0, -1)
+
+
+def is_palindrome_challenge_helper(text, s, e):
+    if s > len(text)/2:
+        return True
+
+    if text[s] != text[e]:
+        return False
+
+    return is_palindrome_challenge_helper(text, s+1, e-1)
+
 
 # digit_match
+def digit_match(int1, int2):
+    return digit_match_helper(int1, int2, 0)
+
+
+def digit_match_helper(int1, int2, count):
+    if int1 % 10 == int2 % 10:
+        count += 1
 
+    if not int1 // 10 or not int2 // 10:
+        return count
 
+    return digit_match_helper(int1//10, int2//10, count)