《leetcode hot100》142. 环形链表 II

Accode:

public class Solution {
    public ListNode detectCycle(ListNode head) {
        ListNode slow = head, fast = head;
        
        while (true) {
            if (fast == null || fast.next == null) return null;
            slow = slow.next;
            fast = fast.next.next;
            if (slow == fast) break;
        }
        
        fast = head;
        while (slow!=fast) {
            slow = slow.next;
            fast = fast.next;
        }
        return slow;
    }
}

over~