876.链表的中间结点（两种解法）

Posted 2022-05-02 *平芜尽处是春山*

解法一：暴力求解法

class Solution 
    public ListNode middleNode(ListNode head) 
        ListNode node = head;
        int size = 0;
        while(node != null) 
            size++;
            node = node.next;
        
        for(int i = 0; i < size/2; i++) 
            head = head.next;
        
        return head;
    

运行截图：

解法二、快慢指针法

class Solution 
    public ListNode middleNode(ListNode head) 
        ListNode low = head,fast = head;
        while(fast != null && fast.next != null) 
            low = low.next;
            fast = fast.next.next;
        
        return low;
    

运行截图：