This is a java program to generate a random graph by generating random number of edges. One important thing to note here is, that we need to decide minimum and maximum number of nodes such that all edges get accommodated. Minimum number of vertices is positive solution to n(n-1) = 2e, where e is number of edges and maximum number of vertices is e+1.
Here is the source code of the Java Program to Create a Random Graph Using Random Edge Generation. The Java program is successfully compiled and run on a Windows system. The program output is also shown below.
//This is a java program to generate a random graph using random edge generation import java.util.HashMap; import java.util.LinkedList; import java.util.List; import java.util.Map; import java.util.Random; import java.util.Scanner; public class Random_Edges_Graph { private Map<Integer, List<Integer>> adjacencyList; public Random_Edges_Graph(int v) { adjacencyList = new HashMap<Integer, List<Integer>>(); for (int i = 1; i <= v; i++) adjacencyList.put(i, new LinkedList<Integer>()); } public void setEdge(int to, int from) { if (to > adjacencyList.size() || from > adjacencyList.size()) System.out.println("The vertices does not exists"); List<Integer> sls = adjacencyList.get(to); sls.add(from); List<Integer> dls = adjacencyList.get(from); dls.add(to); } public List<Integer> getEdge(int to) { if (to > adjacencyList.size()) { System.out.println("The vertices does not exists"); return null; } return adjacencyList.get(to); } public static void main(String args[]) { System.out.println("Enter the number of edges: "); Scanner sc = new Scanner(System.in); int e = sc.nextInt(); try { int minV = (int) Math.ceil((1 + Math.sqrt(1 + 8 * e)) / 2); int maxV = e + 1; Random random = new Random(); int v = Math.abs(random.nextInt(maxV - minV) + minV); System.out.println("Random graph has "+v+" vertices"); Random_Edges_Graph reg = new Random_Edges_Graph(v); int count = 1, to, from; while (count <= e) { to = Math.abs(random.nextInt(v + 1 - 1) + 1); from = Math.abs(random.nextInt(v + 1 - 1) + 1); reg.setEdge(to, from); count++; } System.out .println("THe Adjacency List Representation of the random graph is: "); for (int i = 1; i <= v; i++) { System.out.print(i + " -> "); List<Integer> edgeList = reg.getEdge(i); if (edgeList.size() == 0) System.out.print("null"); else { for (int j = 1;; j++) { if (j != edgeList.size()) System.out.print(edgeList.get(j - 1) + " -> "); else { System.out.print(edgeList.get(j - 1)); break; } } } System.out.println(); } } catch (Exception E) { System.out.println("Something went wrong"); } sc.close(); } }
Output:
$ javac Random_Edges_Graph.java $ java Random_Edges_Graph Enter the number of edges: 5 Random graph has 4 vertices THe Adjacency List Representation of the random graph is: 1 -> 4 -> 4 2 -> 3 -> 3 3 -> 2 -> 4 -> 2 4 -> 1 -> 1 -> 3
Related posts:
Java NIO2 Path API
Lớp Collections trong Java (Collections Utility Class)
Documenting a Spring REST API Using OpenAPI 3.0
Java Program to Find the Median of two Sorted Arrays using Binary Search Approach
Servlet 3 Async Support with Spring MVC and Spring Security
Java Program to Implement Stack using Linked List
Java program to Implement Tree Set
Java Program to Implement Pagoda
Làm thế nào tạo instance của một class mà không gọi từ khóa new?
Java Program to Implement Graph Coloring Algorithm
Spring JDBC
Hướng dẫn tạo và sử dụng ThreadPool trong Java
Apache Commons Collections BidiMap
Guide to the Java TransferQueue
Java – File to Reader
Overview of the java.util.concurrent
Exploring the Spring 5 WebFlux URL Matching
Convert a Map to an Array, List or Set in Java
Spring Boot - Tomcat Deployment
A Guide to LinkedHashMap in Java
Spring MVC Tutorial
Java Switch Statement
Spring Boot - Google Cloud Platform
Java Program to Perform Preorder Non-Recursive Traversal of a Given Binary Tree
CharSequence vs. String in Java
Java Program to Find the Shortest Path from Source Vertex to All Other Vertices in Linear Time
Send email with SMTPS (eg. Google GMail)
Java Program to Implement Booth Algorithm
Spring Security Remember Me
The Guide to RestTemplate
Java Program to Implement Regular Falsi Algorithm
A Guide to Spring Boot Admin