Initial commit

get_max_prefix_sum_original.py

+def get_maximum_prefix_sum(values):
+    if len(values) > 0:
+        candidate = get_maximum_prefix_sum(values[:-1])
+        total = sum(values)  # requires a loop, which makes our recursion slow!
+        if candidate > total:
+            return candidate
+        return total
+    return 0
+
+
+print(get_maximum_prefix_sum([5, -4, 6]))

get_max_prefix_with_helper.py

+def helper(values):
+    if len(values) > 0:
+        candidate, partial_total = helper(values[:-1])
+        total = partial_total + values[-1]
+        if candidate > total:
+            return candidate, total
+        return total, total
+    return 0, 0
+
+
+def get_maximum_prefix_sum(values):
+    result, _ = helper(values)
+    return result
+
+
+print(get_maximum_prefix_sum([5, -4, 6]))
\ No newline at end of file

palindrome.py

+def is_palindrome(text):
+    return is_palindrome_helper(text, 0, len(text)-1)
+
+
+def is_palindrome_helper(text, start, end):
+    if start >= end:
+        return True
+
+    first = text[start].lower()
+    last = text[end].lower()
+
+    if first.isalpha() and last.isalpha():
+        if first == last:
+            return is_palindrome_helper(text, start+1, end-1)
+        else:
+            return False
+    elif not last.isalpha():
+        return is_palindrome_helper(text, start, end-1)
+    else:
+        return is_palindrome_helper(text, start+1, end)
+
+
+print(is_palindrome('Madam, I\'m Adam'))
+print(is_palindrome('Go hang a salami, I\'m a lasagna hog'))
+print(is_palindrome('A man, a plan, a canal–Panama!'))
+