This is a java program to check whether graph contains Eulerian Cycle. The criteran Euler suggested,
1. If graph has no odd degree vertex, there is at least one Eulerian Circuit.
2. If graph as two vertices with odd degree, there is no Eulerian Circuit but at least one Eulerian Path.
3. If graph has more than two vertices with odd degree, there is no Eulerian Circuit or Eulerian Path.
Here is the source code of the Java Program to Check Whether an Undirected Graph Contains a Eulerian Cycle. The Java program is successfully compiled and run on a Windows system. The program output is also shown below.
package com.maixuanviet.graph; import java.util.InputMismatchException; import java.util.Scanner; public class UndirectedEulerianCircuit { private int[][] adjacencyMatrix; private int numberOfNodes; public UndirectedEulerianCircuit(int numberOfNodes, int[][] adjacencyMatrix) { this.numberOfNodes = numberOfNodes; this.adjacencyMatrix = new int[numberOfNodes + 1][numberOfNodes + 1]; for (int sourceVertex = 1; sourceVertex <= numberOfNodes; sourceVertex++) { for (int destinationVertex = 1; destinationVertex <= numberOfNodes; destinationVertex++) { this.adjacencyMatrix[sourceVertex][destinationVertex] = adjacencyMatrix[sourceVertex][destinationVertex]; } } } public int degree(int vertex) { int degree = 0; for (int destinationvertex = 1; destinationvertex <= numberOfNodes; destinationvertex++) { if (adjacencyMatrix[vertex][destinationvertex] == 1 || adjacencyMatrix[destinationvertex][vertex] == 1) { degree++; } } return degree; } public int countOddDegreeVertex() { int count = 0; for (int node = 1; node <= numberOfNodes; node++) { if ((degree(node) % 2) != 0) { count++; } } return count; } public static void main(String... arg) { int number_of_nodes; Scanner scanner = null; try { System.out.println("Enter the number of nodes in the graph"); scanner = new Scanner(System.in); number_of_nodes = scanner.nextInt(); int adjacency_matrix[][] = new int[number_of_nodes + 1][number_of_nodes + 1]; System.out.println("Enter the adjacency matrix"); for (int i = 1; i <= number_of_nodes; i++) { for (int j = 1; j <= number_of_nodes; j++) { adjacency_matrix[i][j] = scanner.nextInt(); } } // make the graph undirected for (int i = 1; i <= number_of_nodes; i++) { for (int j = 1; j <= number_of_nodes; j++) { if (adjacency_matrix[i][j] == 1 && adjacency_matrix[j][i] == 0) { adjacency_matrix[j][i] = 1; } } } UndirectedEulerPath path = new UndirectedEulerPath(number_of_nodes, adjacency_matrix); int count = path.countOddDegreeVertex(); if (count == 0) { System.out .println("As the graph has no odd degree vertex, there is at least one Eulerian Circuit."); } else if (count == 2) { System.out .println("As the graph as two vertices with odd degree, there is no Eulerian Circuit but at least one Eulerian Path."); } else { System.out .println("As the graph has more than two vertices with odd degree, there is no Eulerian Circuit or Eulerian Path."); } } catch (InputMismatchException inputMismatch) { System.out.println("Wrong Input format"); } scanner.close(); } }
Output:
$ javac UndirectedEulerianCircuit.java $ java UndirectedEulerianCircuit Enter the number of nodes in the graph 6 Enter the adjacency matrix 0 1 0 0 0 0 1 0 1 1 0 0 0 1 0 0 0 1 0 1 0 0 1 1 0 0 0 1 0 1 0 0 1 1 1 0 As the graph has more than two vertices with odd degree, there is no Eulerian Circuit or Eulerian Path.
Related posts:
Java Program to Use Boruvka’s Algorithm to Find the Minimum Spanning Tree
Converting a Stack Trace to a String in Java
The DAO with Spring and Hibernate
Spring RequestMapping
REST Web service: Tạo ứng dụng Java RESTful Client với Jersey Client 2.x
A Guide to BitSet in Java
Tiêu chuẩn coding trong Java (Coding Standards)
HttpClient Timeout
Java Stream Filter with Lambda Expression
Mảng (Array) trong Java
Using Custom Banners in Spring Boot
Java Program to Show the Duality Transformation of Line and Point
Java Program to Implement the MD5 Algorithm
Các kiểu dữ liệu trong java
Fixing 401s with CORS Preflights and Spring Security
Java Program to Implement Jarvis Algorithm
Send an email using the SMTP protocol
Java Program to Find a Good Feedback Edge Set in a Graph
Java InputStream to String
Java Program to Emulate N Dice Roller
Java Program to Implement Pairing Heap
Giới thiệu Google Guice – Binding
New Features in Java 13
Server-Sent Events in Spring
Convert Time to Milliseconds in Java
How to Change the Default Port in Spring Boot
Hướng dẫn Java Design Pattern – Interpreter
Java Collections Interview Questions
Integer Constant Pool trong Java
Java Program to Implement Treap
Spring Boot - Google Cloud Platform
Spring REST with a Zuul Proxy