josephus问题链表

以下是使用链表解决Josephus问题的Python代码：

class Node:
    def __init__(self, data):
        self.data = data
        self.next = None

class CircularLinkedList:
    def __init__(self):
        self.head = None

    def add_node(self, data):
        new_node = Node(data)
        if self.head is None:
            self.head = new_node
            new_node.next = self.head
        else:
            current = self.head
            while current.next != self.head:
                current = current.next
            current.next = new_node
            new_node.next = self.head

    def remove_node(self, node):
        if self.head == node:
            current = self.head
            while current.next != self.head:
                current = current.next
            current.next = self.head.next
            self.head = self.head.next
        else:
            current = self.head
            prev = None
            while current.next != self.head:
                prev = current
                current = current.next
                if current == node:
                    prev.next = current.next
                    break

    def get_survivor(self, step):
        current = self.head
        while len(self) > 1:
            for i in range(step - 1):
                current = current.next
            self.remove_node(current)
            current = current.next
        return self.head.data

    def __len__(self):
        current = self.head
        count = 0
        while current:
            count += 1
            current = current.next
            if current == self.head:
                break
        return count

# 示例
cll = CircularLinkedList()
for i in range(1, 41):
    cll.add_node(i)
print(cll.get_survivor(3)) # 输出：4