leetCode 82.Remove Duplicates from Sorted List II

leetCode 82.Remove Duplicates from Sorted List II.

Problem

Given the head of a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list. Return the linked list sorted as well.

Example 1:

Input: head = [1, 2, 3, 3, 4, 4, 5]
Output: [1, 2, 5]

Example 2:

Input: head = [1, 1, 1, 2, 3]
Output: [2, 3]

Constraints:

The number of nodes in the list is in the range [0, 300].
-100 <= Node.val <= 100
The list is guaranteed to be sorted in ascending order.

Solution

var deleteDuplicates = function (head) {
  // new node
  var newHead = new ListNode(0)

  //  define node
  var now = newHead

  // make temporary node
  var tmp = head

  var val = 0

  // 현재 노드를 다 도는 동안 반복
  while (tmp) {
    // 현재 노드
    val = tmp.val

    // 다음 노드랑 현재 노드가 같은지 체크
    if (tmp.next && tmp.next.val === val) {
      tmp = tmp.next
      while (tmp && tmp.val === val) tmp = tmp.next
    } else {
      // 노드를 다시 정의해줌
      now.next = tmp
      now = tmp
      tmp = tmp.next
      now.next = null
    }
  }

  return newHead.next
}