Improved task 2368.

Author: javadev

README.md

@@ -1848,6 +1848,9 @@ implementation 'com.github.javadev:leetcode-in-java:1.12'
 
 | #    |      Title     | Difficulty  | Tag         | Time, ms | Time, %
 |------|----------------|-------------|-------------|----------|---------
+| 2370 |[Longest Ideal Subsequence](src/main/java/g2301_2400/s2370_longest_ideal_subsequence/Solution.java)| Medium | String, Hash_Table, Dynamic_Programming | 28 | 85.71
+| 2369 |[Check if There is a Valid Partition For The Array](src/main/java/g2301_2400/s2369_check_if_there_is_a_valid_partition_for_the_array/Solution.java)| Medium | Array, Dynamic_Programming | 7 | 81.82
+| 2368 |[Reachable Nodes With Restrictions](src/main/java/g2301_2400/s2368_reachable_nodes_with_restrictions/Solution.java)| Medium | Array, Tree, Graph, Hash_Table, Depth_First_Search, Breadth_First_Search | 59 | 85.71
 | 2367 |[Number of Arithmetic Triplets](src/main/java/g2301_2400/s2367_number_of_arithmetic_triplets/Solution.java)| Easy | Array, Enumeration, Hash_Table, Two_Pointers | 3 | 66.67
 | 2366 |[Minimum Replacements to Sort the Array](src/main/java/g2301_2400/s2366_minimum_replacements_to_sort_the_array/Solution.java)| Hard | Array, Math, Greedy | 10 | 28.57
 | 2365 |[Task Scheduler II](src/main/java/g2301_2400/s2365_task_scheduler_ii/Solution.java)| Medium | Array, Simulation, Hash_Table | 70 | 55.56

src/main/java/g2301_2400/s2368_reachable_nodes_with_restrictions/Solution.java

@@ -1,46 +1,44 @@
 package g2301_2400.s2368_reachable_nodes_with_restrictions;
 
 // #Medium #Array #Tree #Graph #Hash_Table #Depth_First_Search #Breadth_First_Search
-// #2022_08_15_Time_88_ms_(42.86%)_Space_201.1_MB_(14.29%)
+// #2022_08_16_Time_59_ms_(85.71%)_Space_89.6_MB_(85.71%)
 
-import java.util.LinkedList;
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Queue;
 
+@SuppressWarnings("unchecked")
 public class Solution {
     public int reachableNodes(int n, int[][] edges, int[] restricted) {
-        LinkedList<Integer>[] adj = new LinkedList[n];
-        for (int i = 0; i < n - 1; i++) {
-            if (adj[edges[i][0]] == null) {
-                LinkedList<Integer> source = new LinkedList<>();
-                source.add(edges[i][1]);
-                adj[edges[i][0]] = source;
-            } else {
-                adj[edges[i][0]].add(edges[i][1]);
-            }
-            if (adj[edges[i][1]] == null) {
-                LinkedList<Integer> dest = new LinkedList<>();
-                dest.add(edges[i][0]);
-                adj[edges[i][1]] = dest;
-            } else {
-                adj[edges[i][1]].add(edges[i][0]);
-            }
+        List<Integer>[] graph = new ArrayList[n];
+        for (int i = 0; i < n; i++) {
+            graph[i] = new ArrayList<>();
         }
-        boolean[] visited = new boolean[n];
-        for (int res : restricted) {
-            visited[res] = true;
+        for (int[] edge : edges) {
+            int src = edge[0];
+            int dest = edge[1];
+            graph[src].add(dest);
+            graph[dest].add(src);
         }
-        int count = 1;
+        Queue<Integer> q = new ArrayDeque<>();
+        boolean[] visited = new boolean[n];
+        q.offer(0);
         visited[0] = true;
-        return countReachableNodes(0, adj, visited, count);
-    }
-
-    private int countReachableNodes(
-            int source, LinkedList<Integer>[] adj, boolean[] visited, int count) {
-        for (int neighbour : adj[source]) {
-            if (!visited[neighbour]) {
-                visited[neighbour] = true;
-                count = countReachableNodes(neighbour, adj, visited, ++count);
+        for (int node : restricted) {
+            visited[node] = true;
+        }
+        int ans = 0;
+        while (!q.isEmpty()) {
+            int vertex = q.poll();
+            ans++;
+            for (int neighbour : graph[vertex]) {
+                if (!visited[neighbour]) {
+                    q.offer(neighbour);
+                    visited[neighbour] = true;
+                }
             }
         }
-        return count;
+        return ans;
     }
 }