题解 | #链表中环的入口结点#
链表中环的入口结点
https://www.nowcoder.com/practice/253d2c59ec3e4bc68da16833f79a38e4
/* public class ListNode { int val; ListNode next = null; ListNode(int val) { this.val = val; } } */ public class Solution { public ListNode EntryNodeOfLoop(ListNode pHead) { if(pHead == null || pHead.next == null){ return null; } ListNode slow = pHead, fast = pHead, ano = pHead; while(fast != null && fast.next != null){ fast = fast.next.next; slow = slow.next; if(fast == slow){ //相遇,表示有环。这时候,慢的和ano每次走一步,相遇即环的入口 while(ano != slow){ slow = slow.next; ano = ano.next; } return ano; } } return null; } }#学习##刷题##每日刷题#