Add solution #841

Author: JoshCrozier

README.md

@@ -252,6 +252,7 @@
 821|[Shortest Distance to a Character](./0821-shortest-distance-to-a-character.js)|Easy|
 824|[Goat Latin](./0824-goat-latin.js)|Easy|
 831|[Masking Personal Information](./0831-masking-personal-information.js)|Medium|
+841|[Keys and Rooms](./0841-keys-and-rooms.js)|Medium|
 844|[Backspace String Compare](./0844-backspace-string-compare.js)|Easy|
 846|[Hand of Straights](./0846-hand-of-straights.js)|Medium|
 867|[Transpose Matrix](./0867-transpose-matrix.js)|Easy|

solutions/0841-keys-and-rooms.js

@@ -0,0 +1,28 @@
+/**
+ * 841. Keys and Rooms
+ * https://leetcode.com/problems/keys-and-rooms/
+ * Difficulty: Medium
+ *
+ * There are n rooms labeled from 0 to n - 1 and all the rooms are locked except for room 0.
+ * Your goal is to visit all the rooms. However, you cannot enter a locked room without
+ * having its key.
+ *
+ * When you visit a room, you may find a set of distinct keys in it. Each key has a number
+ * on it, denoting which room it unlocks, and you can take all of them with you to unlock
+ * the other rooms.
+ *
+ * Given an array rooms where rooms[i] is the set of keys that you can obtain if you visited
+ * room i, return true if you can visit all the rooms, or false otherwise.
+ */
+
+/**
+ * @param {number[][]} rooms
+ * @return {boolean}
+ */
+var canVisitAllRooms = function(rooms) {
+  const set = new Set([0]);
+  for (const key of set) {
+    rooms[key].forEach(value => set.add(value));
+  }
+  return set.size === rooms.length;
+};