Add solution #328

Author: JoshCrozier

README.md

@@ -167,6 +167,7 @@
 290|[Word Pattern](./0290-word-pattern.js)|Easy|
 316|[Remove Duplicate Letters](./0316-remove-duplicate-letters.js)|Medium|
 326|[Power of Three](./0326-power-of-three.js)|Easy|
+328|[Odd Even Linked List](./0328-odd-even-linked-list.js)|Medium|
 334|[Increasing Triplet Subsequence](./0334-increasing-triplet-subsequence.js)|Medium|
 342|[Power of Four](./0342-power-of-four.js)|Easy|
 344|[Reverse String](./0344-reverse-string.js)|Easy|

solutions/0328-odd-even-linked-list.js

@@ -0,0 +1,43 @@
+/**
+ * 328. Odd Even Linked List
+ * https://leetcode.com/problems/odd-even-linked-list/
+ * Difficulty: Medium
+ *
+ * Given the head of a singly linked list, group all the nodes with odd indices together followed
+ * by the nodes with even indices, and return the reordered list.
+ *
+ * The first node is considered odd, and the second node is even, and so on.
+ *
+ * Note that the relative order inside both the even and odd groups should remain as it was in
+ * the input.
+ *
+ * You must solve the problem in O(1) extra space complexity and O(n) time complexity.
+ */
+
+/**
+ * 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 oddEvenList = function(head) {
+  if (!head) return head;
+
+  const even = head.next;
+  let odd = head;
+
+  while (odd.next && odd.next.next) {
+    const pointer = odd.next;
+    odd.next = odd.next.next;
+    odd = odd.next;
+    pointer.next = odd.next;
+  }
+
+  odd.next = even;
+  return head;
+};