Completed assignment

part-1.py

@@ -4,17 +4,36 @@
 # the appropriate comment.
 
 # factorial
-
+def factorial(n):
+    if n < 0:
+        raise ValueError("Factorial is not defined for negative numbers.")
+    if n == 0:
+        return 1
+    return n * factorial(n - 1)
 
 
 # reverse
-
+def reverse(text):
+    if len(text) <= 1:
+        return text
+    return text[-1] + reverse(text[:-1])
 
 
 # bunny
-
+def bunny(count):
+    if count == 0:
+        return 0
+    return 2 + bunny(count - 1)
 
 
 # is_nested_parens
-
+def is_nested_parens(parens):
+    def helper(start, end):
+        if start > end:
+            return True
+        if parens[start] != '(' or parens[end] != ')':
+            return False
+        return helper(start + 1, end - 1)
+
+    return helper(0, len(parens) - 1)
 

part-2.py

@@ -4,13 +4,40 @@
 # the appropriate comment.
 
 # search
-
+def search(array, query):
+    if not array:
+        return False
+    if array[0] == query:
+        return True
+    return search(array[1:], query)
 
 
 # is_palindrome
+def is_palindrome(text):
+    def helper(left, right):
+        if left >= right:
+            return True
+        if text[left] != text[right]:
+            return False
+        return helper(left + 1, right - 1)
 
+    return helper(0, len(text) - 1)
 
 
 # digit_match
+def digit_match(apples, oranges):
+    if apples == 0 or oranges == 0:
+        return 1 if apples == 0 and oranges == 0 else 0
+
+    match = 0
+    if apples % 10 == oranges % 10:
+        match = 1
+
+    remaining_apples = apples // 10
+    remaining_oranges = oranges // 10
+
+    if remaining_apples == 0 and remaining_oranges == 0:
+        return match
 
+    return match + digit_match(remaining_apples, remaining_oranges)