203. Remove Linked List Elements.md

203. Remove Linked List Elements

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leetcode Daily Challenge on July 20th, 2020.

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Difficulty : Easy

Related Topics : LinkedList

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Remove all elements from a linked list of integers that have value val.

Example:

Input:  1->2->6->3->4->5->6, val = 6
Output: 1->2->3->4->5

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Solution

• mine
  • Java
    • Runtime: 1 ms, faster than 90.05%, Memory Usage: 40.6 MB, less than 32.91% of Java online submissions

      // O(N)time
      // O(1)space
      public ListNode removeElements(ListNode head, int val) {
          ListNode res = new ListNode();
          res.next = head;
          ListNode t = res;
          while(t.next != null){
              if(t.next.val == val){
                  while(t.next != null && t.next.val == val){
                      t.next = t.next.next;
                  }    
              }else{
                  t = t.next;
              }
          }
          return res.next;
      }
      

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