java--数据结构--链表

1.查找链表中点，使用两个指针

ListNode searchMidNode(ListNode head) { ListNode slow = head, fast = head; while(fast && fast.next) { slow = slow.next; fast = fast.next.next; } if(fast) { return slow; } if(fast.next) { return slow.next; } }

2.查找链表是否有环，使用两个指针

ListNode isCircle(ListNode head) { ListNode slow = head, fast = head; while(fast && fast.next) { slow = slow.next; fast = fast.next.next; } if(slow == fast) { return true; } return false; }

3.有环链表的长度

void circleLen(LinkNode head) { ListNode slow = head, fast = head; int len = 1; while(fast && fast.next) { slow = slow.next; fast = fast.next.next; len++; if(slow == fast) { break; } } }