Remove Linked List Elements Problem
Description
LeetCode Problem 203.
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:
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Input: head = [1,2,6,3,4,5,6], val = 6
Output: [1,2,3,4,5]
Example 2:
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Input: head = [], val = 1
Output: []
Example 3:
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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
Sample C++ Code
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/**
* 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) {}
* };
*/
class Solution {
public:
ListNode* removeElements(ListNode* head, int val) {
if (head == NULL)
return head;
ListNode* curr = head;
while (curr->next != NULL) {
if (curr->next->val == val) {
curr->next = curr->next->next;
} else {
curr = curr->next;
}
}
if (head->val == val)
head = head->next;
return head;
}
};