原题链接

LeetCode

function deleteDuplicates(head: ListNode | null): ListNode | null {
   let current = head;
   while(current) {
       if(current && current.val === current.next?.val) {
           let prev = current;
           while(prev && prev.next?.val === current.val) {
              prev = prev.next;
           }
          current.next = prev.next;
       }
       current = current.next;
   }
   return head;
};