Dragonfly - Lina Martinez

part-1.py

@@ -4,17 +4,49 @@
 # the appropriate comment.
 
 # factorial
-
+def factorial(n):
+    if n < 0:
+        raise ValueError
+    elif n == 0:
+        return 1
+
+    return n * factorial(n - 1)
 
 
 # reverse
-
+def reverse(text):
+    if len(text) <= 1:
+        return text
+
+    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 len(parens) == 0:
+        return True
+
+    if parens[0] != "(" or parens[-1] != ")":
+        return False
+
+    return is_nested_parens(parens[1:-1])
+
+# Challenge is_nested_parens
+def is_nested_parens(parens):
+    def check_first_and_last(start, end):
+        if start > end:
+            return True
+        if parens[start] != '(' or parens[end] != ')':
+            return False
+        return check_first_and_last(start + 1, end - 1)
+
+    return check_first_and_last(0, len(parens) - 1)
 

part-2.py

@@ -4,13 +4,61 @@
 # the appropriate comment.
 
 # search
-
+def search(array, query):
+    def check_one_element(index):
+        if index == len(array):
+            return False
+        elif array[index] == query:
+            return True
+
+        return check_one_element(index+1)
+
+    return check_one_element(0)
 
 
 # is_palindrome
-
+def is_palindrome(text):
+    def check_chars(for_index, back_index):
+        if for_index >= back_index:
+            return True
+        elif text[for_index] != text[back_index]:
+            return False
+
+        return check_chars(for_index+1, back_index-1)
+
+    return check_chars(0, len(text)-1)
 
 
 # digit_match
+def digit_match(num_1, num_2):
+    num_1 = str(num_1)
+    num_2 = str(num_2)
+
+    def count_matches(index_1, index_2, counter):
+        if index_1 < 0 or index_2 < 0:
+            return counter
+
+        if num_1[index_1] == num_2[index_2]:
+            counter += 1
+
+        return count_matches(index_1 - 1, index_2 - 1, counter)
+
+    return count_matches(len(num_1) - 1, len(num_2) - 1, 0)
+
+# digit match without casting int to str
+def digit_match(num_1, num_2):
+    if num_1 == 0 and num_2 == 0:
+        return 1
+
+    def count_matches(n1, n2):
+        if n1 == 0 or n2 == 0:
+            return 0
+
+        if n1 % 10 == n2 % 10:
+            count = 1
+        else:
+            count = 0
 
+        return count + count_matches(n1 // 10, n2 // 10)
 
+    return count_matches(num_1, num_2)