141. Linked List Cycle
难度: Easy
刷题内容
原题连接
- https://leetcode.com/problems/linked-list-cycle
内容描述
Given a linked list, determine if it has a cycle in it.
Follow up:
Can you solve it without using extra space?
解题方案
思路 1 **- 时间复杂度: O(N)*- 空间复杂度: O(1)***
快慢指针
java
public class Solution {
public boolean hasCycle(ListNode head) {
if (head == null){
return false;
}
ListNode fast = head;
ListNode slow = head;
while (fast != null && slow != null && fast.next != null){
fast = fast.next.next;
slow = slow.next;
if (slow == fast){
return true;
}
}
return false;
}
}
