July_20.cpp

/**
 * 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) {
        ListNode* l = head;
        
        if(head == NULL)
            return NULL;
        
        while(l->next != NULL)
            if(l->next->val == val)
                l->next = l->next->next;
            else
                l = l->next;
            
        if(head->val == val)
            head = head->next;
        
        return head;
    }
};