Create DFS(recursive).java

youssefAli11997 · web-flow · commit 71ab3e2eb64e · 2017-10-16T21:18:05.000+02:00
diff --git a/DepthFirstSearch/Java/DFS(recursive).java b/DepthFirstSearch/Java/DFS(recursive).java
@@ -0,0 +1,53 @@
+import java.util.ArrayList;
+import java.util.Scanner;
+
+public class DFS_Recursive {
+
+	/**
+	 * @author Youssef Ali(https://github.com/youssefAli11997/)
+	 */
+	
+	private static boolean[] visited;
+	private static ArrayList<Integer> AdjList[];
+	
+	public static void DFS_recursive(int parent){
+		visited[parent] = true;
+		System.out.print(parent+" ");
+		for(int child : AdjList[parent]){
+			if(visited[child])
+				continue;
+			DFS_recursive(child);
+		}
+	}
+	
+	@SuppressWarnings("unchecked")
+	public static void main(String[] args) {
+		Scanner in = new Scanner(System.in);
+		
+		System.out.println("How many nodes?");
+		int nodes = in.nextInt();
+		
+		visited = new boolean[nodes];
+		AdjList = new ArrayList[nodes];
+		for(int i=0; i<nodes; i++)
+			AdjList[i] = new ArrayList<Integer>();
+		
+		System.out.println("How many edges?");
+		int edges = in.nextInt();
+		
+		for(int i=0; i<edges; i++){
+			System.out.println("To indicate that u is connected to v, type: u v");
+			int x = in.nextInt();
+			int y = in.nextInt();
+			// Assuming that it's an undirected graph
+			AdjList[x].add(y);
+			AdjList[y].add(x);
+		}
+		System.out.println("Source node?");
+		int source = in.nextInt();
+		
+		DFS_recursive(source);
+		System.out.println();
+	}
+
+}
