LintCode:M-帶環連結串列
阿新 • • 發佈:2019-01-22
給定一個連結串列,判斷它是否有環。
您在真實的面試中是否遇到過這個題? Yes 樣例給出 -21->10->4->5, tail connects to node index 1,返回 true
/** * Definition for ListNode. * public class ListNode { * int val; * ListNode next; * ListNode(int val) { * this.val = val; * this.next = null; * } * } */ public class Solution { /** * @param head: The first node of linked list. * @return: True if it has a cycle, or false */ public boolean hasCycle(ListNode head) { if(head==null) return false; ListNode fast = head; ListNode slow = head; while(fast.next!=null && fast.next.next!=null){ fast = fast.next.next; slow = slow.next; if(fast==slow) return true; } return false; } }