題目 :
Given a linked list, determine if it has a cycle in it.
To represent a cycle in the given linked list, we use an integer pos which represents the position (0-indexed) in the linked list where tail connects to. If pos is -1, then there is no cycle in the linked list.
大意 :
判斷 Link list 是否有cycle 條件.
1 class Solution { 2 public: 3 4 bool hasCycle(ListNode *head) { 5 6 ListNode * fast = head; 7 ListNode * slow = head; 8 9 while (fast != NULL && fast->next != NULL) 10 { 11 fast = fast->next->next; 12 slow = slow->next; 13 if (fast == slow) 14 return true; 15 } 16 17 return false; 18 } 19 };