Remove Linked List Elements

Question

Problem Statement

Remove all elements from a linked list of integers that have value val.

Example

Given 1->2->3->3->4->5->3, val = 3, you should return the list as 1->2->4->5

题解

删除链表中指定值,找到其前一个节点即可,将 next 指向下一个节点即可。

Python

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

class Solution(object):
def removeElements(self, head, val):
"""
:type head: ListNode
:type val: int
:rtype: ListNode
"""
dummy = ListNode(0)
dummy.next = head
curr = dummy
while curr.next is not None:
if curr.next.val == val:
curr.next = curr.next.next
else:
curr = curr.next

return dummy.next

Java

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/**
* Definition for singly-linked list.
* public class ListNode {
* int val;
* ListNode next;
* ListNode(int x) { val = x; }
* }
*/
public class Solution {
/**
* @param head a ListNode
* @param val an integer
* @return a ListNode
*/
public ListNode removeElements(ListNode head, int val) {
ListNode dummy = new ListNode(0);
dummy.next = head;
ListNode curr = dummy;
while (curr.next != null) {
if (curr.next.val == val) {
curr.next = curr.next.next;
} else {
curr = curr.next;
}
}

return dummy.next;
}
}

源码分析

while 循环中使用curr.next较为方便,if 语句中比较时也使用curr.next.val也比较简洁,如果使用curr会比较难处理。

复杂度分析


  


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