Joseph Ring problem

problem
Given a chain header node head, And a positive number m
Start from scratch , Count to every time m Kill the current node
Then the next node of the killed node starts from 1 Start counting again ,
Go round and round until there is only one node left , Return the last node .

Example
A little

thought
Recurrence of violence , This type of topic belongs to periodic function , When you encounter this kind of problem, you can use y = x %i How to do it

Code

public static Node josephusKill1(Node head, int m) {
    
		if(head == null || head.next == head||m<1) {
    
			return head;
		}
		Node cur = head;
		int size = 0;
		while(cur != null) {
    
			size++;
			cur = cur.next;
		}
		int live = getLive(size,m);
		while(--live>=0) {
    
			head = head.next;
		}
		head.next = head;
		return head;
	}
	// As long as there is a razor feeling, the function starts from y = x % i  Start ( Regular slash )
	public static int getLive(int size, int m) {
    
		if(size == 1) {
    
			return 1;
		}
		return ((getLive(size-1, m) + m-1) % size) + 1;
	}
	public static class Node{
     
		Node next;
		int val;
		public Node(int val ) {
    
			this.val = val;
		}
	}