LeetCodeProblems/14-Optimal.py at main · EmperorArthurIX/LeetCodeProblems · GitHub

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def rotateRight(self, head: Optional[ListNode], k: int) -> Optional[ListNode]:
    if not head:
        return
    if head and not head.next:
        return head
    if k == 0:
        return head                 # Time saving checks

    curr = head
    tail = None
    size = 0
    while curr:
        tail = curr
        curr = curr.next
        size += 1                   # Calculating size

    if k%size == 0:                 # Time saving
        return head

    tail.next = head                # Making cyclic to ease process

    curr = head
    for i in range(2*size - k%size - 1):    # Which Node will become TAIL after these many rotations
        curr = curr.next
    ans = curr.next                         # Mark Head
    curr.next = None                        # Un-Cycle the list

    return ans