题解 | 约瑟夫环

class Node:
    No: int
    Next = None  # 链表下一个
    Pre = None  # 链表上一个

    def __init__(self, no) -> None:
        self.No = no


def CreatLink(n: int):
    head = Node(0)
    head.Next = head
    head.Pre = head
    tail = head
    for i in range(1, n):
        tail.Next = Node(i)
        tail.Next.Pre = tail
        tail = tail.Next
    tail.Next = head
    head.Pre = tail
    return head


def run(n: int, k: int, m: int):
    head = CreatLink(n)
    for i in range(k):
        head = head.Next
    while head.Next != head:
        for i in range(m - 2):
            head = head.Next
        #print(head.Next.No)
        head.Next = head.Next.Next
        head.Next.Next.Pre = head
        head = head.Next
    print(head.No)


if __name__ == "__main__":
    n, k, m = map(int, input().split())
    run(n, k, m)