diff --git a/problems/0019.删除链表的倒数第N个节点.md b/problems/0019.删除链表的倒数第N个节点.md index 3499ab9d..62fe4f8b 100644 --- a/problems/0019.删除链表的倒数第N个节点.md +++ b/problems/0019.删除链表的倒数第N个节点.md @@ -188,18 +188,20 @@ TypeScript: ```typescript function removeNthFromEnd(head: ListNode | null, n: number): ListNode | null { let newHead: ListNode | null = new ListNode(0, head); - let slowNode: ListNode | null = newHead, - fastNode: ListNode | null = newHead; - for (let i = 0; i < n; i++) { - fastNode = fastNode.next; + //根据leetcode题目的定义可推断这里快慢指针均不需要定义为ListNode | null。 + let slowNode: ListNode = newHead; + let fastNode: ListNode = newHead; + + while(n--) { + fastNode = fastNode.next!; //由虚拟头节点前进n个节点时,fastNode.next可推断不为null。 } - while (fastNode.next) { + while(fastNode.next) { //遍历直至fastNode.next = null, 即尾部节点。 此时slowNode指向倒数第n个节点。 fastNode = fastNode.next; - slowNode = slowNode.next; + slowNode = slowNode.next!; } - slowNode.next = slowNode.next.next; - return newHead.next; -}; + slowNode.next = slowNode.next!.next; //倒数第n个节点可推断其next节点不为空。 + return newHead.next; +} ``` 版本二(计算节点总数法):