Accelerate recursion- Naomi Quinones

part-1.py

@@ -5,16 +5,59 @@
 
 # factorial
 
-
+def factorial(n):
+    if n < 0:
+        raise ValueError
+    if n == 0:
+        return 1
+    if n > 0:
+        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
+    if count == 1:
+        return 2
+
+    return 2 + bunny(count -1)
 
 # is_nested_parens
 
-
+def is_nested_parens(parens):
+    if len(parens) == 0:
+        return True
+    if len(parens) == 1:
+        return False
+    return (parens[0] == "(" and parens[-1] == ")") and is_nested_parens(parens[1:-1])
+
+# CHALLENGE FOR is_nested_parens
+def is_nested_parens2(parens):
+    if len(parens) == 0:
+        return True
+    if len(parens) == 1:
+        return False
+    if len(parens) == 2:
+        return (parens[0] == "(" and parens[-1] == ")")
+
+    front_index = 1
+    back_index = len(parens)-1
+
+    def are_matched(parens,front_index,back_index):
+        if len(parens) % 2 == 1:
+            return False
+        if front_index > len(parens) // 2 or back_index <= len(parens) // 2:
+            return True
+        return parens[front_index] == "(" and parens[back_index] == ")" and are_matched(parens, front_index+1, back_index-1)
+
+    return (parens[0] == "(" and parens[-1] == ")") and are_matched(parens,front_index,back_index)

part-2.py

@@ -5,12 +5,49 @@
 
 # search
 
-
+def search(array, query):
+    if array == []:
+        return False
+    if array[0] == query:
+        return True
+    return search(array[1:], query)
 
 # is_palindrome
-
-
+def is_palindrome(text):
+    if len(text) <= 1:
+        return True
+    return (text[0] == text[-1]) and is_palindrome(text[1:-1])
+
+# CHALLENGE FOR is_palindrome
+def is_palindrome2(text):
+    tlen = len(text)
+    if tlen <= 1:
+        return True
+    if tlen <= 3:
+        return (text[0] == text[-1])
+
+    front_index = 1
+    back_index = tlen - 2
+
+    def chars_match(text, front_index, back_index):
+        if front_index > len(text) // 2 or back_index < len(text) //2:
+            return True
+        return (text[front_index] == text[back_index]) and chars_match(text,front_index+1,back_index-1)
+
+    return (text[0] == text[-1]) and chars_match(text, front_index, back_index)
 
 # digit_match
 
-
+def digit_match(num1,num2):
+    n1 = str(num1)
+    n2 = str(num2)
+    if not n1 or not n2:
+        return 0
+
+    match = 1 if n1[-1] == n2[-1] else 0
+
+    if len(n1) == 1 or len(n2) == 1:
+        return match
+    else:
+        return match + digit_match(n1[:-1],n2[:-1])
+