HackMD
876.Middle of the Linked List
tags: Easy,Linked List,Two Pointers
876. Middle of the Linked List
題目描述
Given the head of a singly linked list, return the middle node of the linked list.
If there are two middle nodes, return the second middle node.
範例
Example 1:
Input: head = [1,2,3,4,5]
Output: [3,4,5]
Explanation: The middle node of the list is node 3.
Example 2:
Input: head = [1,2,3,4,5,6]
Output: [4,5,6]
Explanation: Since the list has two middle nodes with values 3 and 4, we return the second one.
Constraints:
- The number of nodes in the list is in the range
[1, 100]. 1 <= Node.val <= 100
解答
Python
# Definition for singly-linked list.
# class ListNode:
# def __init__(self, val=0, next=None):
# self.val = val
# self.next = next
class Solution:
def middleNode(self, head: Optional[ListNode]) -> Optional[ListNode]:
slow = fast = head
while fast and fast.next:
slow, fast = slow.next, fast.next.next
return slow
Kobe Dec 5, 2022
Javascript
function middleNode(head) {
let slow = head;
let fast = head;
while (fast && fast.next) {
slow = slow.next;
fast = fast.next.next;
}
return slow;
}
Marsgoat Dec 5, 2022
C#
public class Solution {
public ListNode MiddleNode(ListNode head) {
var slow = head;
var fast = head;
while (fast.next != null) {
slow = slow.next;
fast = fast.next;
if (fast.next == null) break;
fast = fast = fast.next;
}
return slow;
}
}
Jim Dec 5, 2022
