reverse list

Author: ivanmmarkovic

recursion/reverse-linked-list.py

@@ -0,0 +1,18 @@
+class ListNode:
+    def __init__(self, val: int = None, next = None):
+        self.val = val
+        self.next = next
+
+
+def reverse_linked_list(node: ListNode) -> ListNode:
+    if node is None:
+        return None
+    elif node.next is None:
+        return node
+    else:
+        next_node: ListNode = node.next
+        node.next = None
+        rest: ListNode = reverse_linked_list(next_node)
+        next_node.next = node
+        return rest
+

recursion/reverse-list.py

@@ -0,0 +1,29 @@
+nums: list = [1, 2, 3, 4, 5]
+
+
+def reverse_rec(elements: list):
+
+    def reverse_list_helper(values: list, start: int, end: int):
+        if start < end:
+            values[start], values[end] = values[end], values[start]
+            reverse_list_helper(values, start + 1, end - 1)
+
+    reverse_list_helper(elements, 0, len(elements) - 1)
+
+
+print(nums)
+reverse_rec(nums)
+print(nums)
+
+
+def reverse_iterative(elements: list):
+    start: int = 0
+    end: int = len(elements) - 1
+    while start < end:
+        elements[start], elements[end] = elements[end], elements[start]
+        start += 1
+        end -= 1
+
+
+reverse_iterative(nums)
+print(nums)