Add solution #82

Author: JoshCrozier

README.md

@@ -77,6 +77,7 @@
 78|[Subsets](./0078-subsets.js)|Medium|
 80|[Remove Duplicates from Sorted Array II](./0080-remove-duplicates-from-sorted-array-ii.js)|Medium|
 81|[Search in Rotated Sorted Array II](./0081-search-in-rotated-sorted-array-ii.js)|Medium|
+82|[Remove Duplicates from Sorted List II](./0082-remove-duplicates-from-sorted-list-ii.js)|Medium|
 83|[Remove Duplicates from Sorted List](./0083-remove-duplicates-from-sorted-list.js)|Easy|
 86|[Partition List](./0086-partition-list.js)|Medium|
 88|[Merge Sorted Array](./0088-merge-sorted-array.js)|Easy|

solutions/0082-remove-duplicates-from-sorted-list-ii.js

@@ -0,0 +1,37 @@
+/**
+ * 82. Remove Duplicates from Sorted List II
+ * https://leetcode.com/problems/remove-duplicates-from-sorted-list-ii/
+ * Difficulty: Medium
+ *
+ * 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.
+ */
+
+/**
+ * Definition for singly-linked list.
+ * function ListNode(val, next) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.next = (next===undefined ? null : next)
+ * }
+ */
+/**
+ * @param {ListNode} head
+ * @return {ListNode}
+ */
+var deleteDuplicates = function(head) {
+  const result = new ListNode();
+  let previous = null;
+  let tail = result;
+
+  while (head) {
+    if (head.val !== head.next?.val && head.val !== previous) {
+      tail.next = new ListNode(head.val);
+      tail = tail.next;
+    }
+    previous = head.val;
+    head = head.next;
+  }
+
+  return result.next;
+};