CPP

Remove Linked List Elements leetcode

class Solution {
public:
    ListNode* removeElements(ListNode* head, int val) {
        
        /*while (head == NULL){
            return head;
        }
        No need for this funtion since we gotta return head in the end of the funtion anyways so this case wud be included
        */
        
        while (head != NULL && head -> val == val){
            head = head -> next;
        }
        ListNode* curr = head;
        while (curr != NULL && curr -> next != NULL){
            if (curr -> next -> val == val){
                curr -> next = curr -> next -> next;
            }
            else {
                curr = curr -> next;
            }
        }
    return head;
    }
};

Delete Node in a Linked List leetcode

class Solution {
public:
    void deleteNode(ListNode* node) {
        //Make the given node to the next node and delete one of them since they now same
        //Say linked list is 4 -> 5 -> 1 -> 9, node = 5
        
        node -> val = node -> next -> val;
        
        //Now it'll be 4 -> 1 -> 1 -> 9, now our node is the first 1
        
        node -> next = node -> next -> next;
        
        //Now it'll be 4 -> 1 -> 9 (the second 1's next link is cut off)
        //That's the whole answer we don't have to return anything
    }
};