841. Keys and Rooms

Author: a-khakimov

leetcode-scala/src/main/scala/LeetCode75/Graphs_DFS/841. Keys and Rooms.sc

@@ -0,0 +1,17 @@
+object Solution {
+  def dfs(graph: Map[Int, List[Int]], start: Int, visited: Set[Int] = Set()): Set[Int] = {
+    if (visited.contains(start)) visited
+    else graph.getOrElse(start, Nil).foldLeft(visited + start)(
+      (acc, neighbor) => dfs(graph, neighbor, acc)
+    )
+  }
+
+  def canVisitAllRooms(rooms: List[List[Int]]): Boolean = {
+    val graph = rooms.zipWithIndex.map(r => r._2 -> r._1).toMap
+    val visited = dfs(graph, 0)
+    visited.size == graph.size
+  }
+}
+
+Solution.canVisitAllRooms(List(List(1), List(2), List(3), Nil))
+Solution.canVisitAllRooms(List(List(1, 3), List(3, 0, 1), List(2), List(0)))