LeetCode-面试题18-删除链表的节点

输入: head = [4,5,1,9], val = 5
输出: [4,1,9]
解释: 给定你链表中值为 5 的第二个节点，那么在调用了你的函数之后，该链表应变为 4 -> 1 -> 9.

输入: head = [4,5,1,9], val = 1
输出: [4,5,9]
解释: 给定你链表中值为 1 的第三个节点，那么在调用了你的函数之后，该链表应变为 4 -> 5 -> 9.

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
class Solution {
    public ListNode deleteNode(ListNode head, int val) {
        if (head == null) {
            return head;
        }
        if (head.val == val) {
            return head.next;
        }
        ListNode res = head;
        while(res.next!=null&&res.next.val!=val){
            res = res.next;
        }
        if(res.next!=null){
            res.next = res.next.next;
        }
        return head;
    }
}

# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution:
    def deleteNode(self, head: ListNode, val: int) -> ListNode:
        if head.val == val: return head.next
        res = head
        while res.next and res.next.val!=val:
            res = res.next
        if res.next:
            res.next = res.next.next
        return head