Add solution #672

Author: JoshCrozier

README.md

@@ -505,6 +505,7 @@
 669|[Trim a Binary Search Tree](./0669-trim-a-binary-search-tree.js)|Medium|
 670|[Maximum Swap](./0670-maximum-swap.js)|Medium|
 671|[Second Minimum Node In a Binary Tree](./0671-second-minimum-node-in-a-binary-tree.js)|Easy|
+672|[Bulb Switcher II](./0672-bulb-switcher-ii.js)|Medium|
 680|[Valid Palindrome II](./0680-valid-palindrome-ii.js)|Easy|
 684|[Redundant Connection](./0684-redundant-connection.js)|Medium|
 686|[Repeated String Match](./0686-repeated-string-match.js)|Easy|

solutions/0672-bulb-switcher-ii.js

@@ -0,0 +1,32 @@
+/**
+ * 672. Bulb Switcher II
+ * https://leetcode.com/problems/bulb-switcher-ii/
+ * Difficulty: Medium
+ *
+ * There is a room with n bulbs labeled from 1 to n that all are turned on initially, and four
+ * buttons on the wall. Each of the four buttons has a different functionality where:
+ * - Button 1: Flips the status of all the bulbs.
+ * - Button 2: Flips the status of all the bulbs with even labels (i.e., 2, 4, ...).
+ * - Button 3: Flips the status of all the bulbs with odd labels (i.e., 1, 3, ...).
+ * - Button 4: Flips the status of all the bulbs with a label j = 3k + 1 where k = 0, 1, 2, ...
+ *   (i.e., 1, 4, 7, 10, ...).
+ * - You must make exactly presses button presses in total. For each press, you may pick any
+ *   of the four buttons to press.
+ *
+ * Given the two integers n and presses, return the number of different possible statuses after
+ * performing all presses button presses.
+ */
+
+/**
+ * @param {number} n
+ * @param {number} presses
+ * @return {number}
+ */
+var flipLights = function(n, presses) {
+  if (presses === 0) return 1;
+  if (n === 1) return presses >= 1 ? 2 : 1;
+  if (n === 2) return presses === 1 ? 3 : 4;
+  if (presses === 1) return 4;
+  if (presses === 2) return 7;
+  return 8;
+};