added rotate_list.py

Author: Pl4tt

python/datastructures/rotate_list.py

@@ -0,0 +1,59 @@
+class ListNode:
+    def __init__(self, val=0, next=None):
+        self.val = val
+        self.next = next
+    
+    def __str__(self):
+        root = self
+        arr = []
+
+        while root:
+            arr.append(root.val)
+            root = root.next
+        
+        return str(arr)
+
+
+def rotate_right(lst: ListNode, k: int) -> ListNode:
+    if lst is None:
+        return None
+    if lst.next is None:
+        return lst
+    
+    k %= get_length(lst)
+    
+    for _ in range(k):
+        lst = rotate_r(lst)
+        
+    return lst
+    
+def rotate_r(lst):
+    root = lst
+    
+    while root.next.next:
+        root = root.next
+
+    root.next.next = lst
+    l2 = root.next
+    root.next = None
+
+    return l2
+
+def get_length(lst: ListNode) -> int:
+    l = 0
+    copy = lst
+    
+    while copy.next:
+        l += 1
+        copy = copy.next
+    
+    return l+1
+        
+
+
+
+
+if __name__ == "__main__":
+    lst = ListNode(1, ListNode(2, ListNode(3, ListNode(4, ListNode(5)))))
+
+    print(rotate_right(lst, 222223))