大纲
题目
地址
https://leetcode.com/problems/remove-linked-list-elements/description/
内容
Given the head of a linked list and an integer val, remove all the nodes of the linked list that has Node.val == val, and return the new head.
Example 1:
Input: head = [1,2,6,3,4,5,6], val = 6
Output: [1,2,3,4,5]
Example 2:
Input: head = [], val = 1
Output: []
Example 3:
Input: head = [7,7,7,7], val = 7
Output: []
Constraints:
- The number of nodes in the list is in the range [0, 10^4^].
- 1 <= Node.val <= 50
- 0 <= val <= 50
解题
这题就是要求在单向链表中删除给定值的元素，然后返回新的链表头结点。
思路就是寻找节点（cur）后第一个不是给定值的节点(checkNode)，然后让(cur的)next指针指向它(checkNode)。之后对找到的新节点继续做此类处理。
cpp
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) {}
};
class Solution {
public:
ListNode* removeElements(ListNode* head, int val) {
ListNode* dummy = new ListNode(0, head);
ListNode* cur = dummy;
while (cur != nullptr && cur->next != nullptr) {
ListNode* checkNode = cur->next;
while (checkNode != nullptr && checkNode->val == val) {
checkNode = checkNode->next;
}
cur->next = checkNode;
cur = checkNode;
}
return dummy->next;
}
};