Given a linked list, determine if it has a cycle in it.
Follow up:
Can you solve it without using extra space?
参考博客：链表环状检测
package cn.magicdu;
import cn.magicdu.extra.ListNode;
public class _114_Linked_List_Cycle {
public boolean hasCycle(ListNode head) {
ListNode fast = head, slow = head;
while (fast != null && fast.next != null) {
fast = fast.next.next;
slow = slow.next;
if (slow == fast) {
return true;
}
}
return false;
}
}