代码随想录.力扣.链表.203.移除链表元素-创新互联
题目:
网站标题:代码随想录.力扣.链表.203.移除链表元素-创新互联
文章转载:http://azwzsj.com/article/cocdee.html
给你一个链表的头节点 head
和一个整数 val
,请你删除链表中所有满足 Node.val == val
的节点,并返回 新的头节点 。
示例 1:
输入:head = [1,2,6,3,4,5,6], val = 6 输出:[1,2,3,4,5]
示例 2:
输入:head = [], val = 1 输出:[]
示例 3:
输入:head = [7,7,7,7], val = 7 输出:[]
提示:
- 列表中的节点数目在范围
[0, 104]
内 1<= Node.val<= 50
0<= val<= 50
class Solution {
public:
ListNode* removeElements(ListNode* head, int val) {
while (head != NULL && head->val == val){
ListNode* tmp = head;
head = head->next;
delete tmp;
}
ListNode* cur = head;
while (cur != NULL && cur->next != NULL){
if (cur->next->val == val){
ListNode* tmp = cur->next;
cur->next = cur->next->next;
delete tmp;
}else{
cur = cur->next;
}
}
return head;
}
};
# 头插法
class Solution {
public:
ListNode* removeElements(ListNode* head, int val) {
ListNode* dummyhead = new ListNode(0);
dummyhead->next = head;
ListNode* cur = dummyhead;
while (cur->next != NULL){
if (cur->next->val == val){
ListNode* tmp = cur->next;
cur->next = cur->next->next;
delete tmp;
}else{
cur = cur->next;
}
}
head = dummyhead->next;
delete dummyhead;
return head;
}
};
关键思路:单链表定义:
Definition for singly-linked list.
struct ListNode {
int val;
ListNode *next;
ListNode() : val(0), next(nullptr) {}
ListNode(int x) : val(x), next(nullptr) {}
ListNode(int x, ListNode *next) : val(x), next(next) {}
};
- 印象中头插法比较常用,注意头插法dummyhead节点的定义
- 基本上需要使用while
- C++里面需要手动删除内存中的被去除的链表节点
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网站标题:代码随想录.力扣.链表.203.移除链表元素-创新互联
文章转载:http://azwzsj.com/article/cocdee.html