题解 | #链表中环的入口结点#
链表中环的入口结点
http://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) {
ListNode fast = pHead;
ListNode slow = pHead;
while(fast != null && fast.next != null){
fast = fast.next.next;
slow = slow.next;
if(slow == fast){
break;
}
}
if(fast == null || fast.next == null){
return null;
}
slow = pHead;
while(fast != slow){
fast = fast.next;
slow = slow.next;
}
return slow;
}
}