algorithm/Java
1
0
Fork 0
mirror of https://github.com/TheAlgorithms/Java.git synced 2025-12-19 07:00:35 +08:00
Code Issues Packages Projects Releases Wiki Activity

feat: Add Hierholzer's Algorithm for Eulerian Circuits (#6726)

Browse Source 
* feat: Add Hierholzer's Algorithm for Eulerian Circuits

* fix: Add more test cases to improve code coverage

* feat: Add Hierholzer's Algorithm for Eulerian Circuits

* fix: Apply clang-format after merge

* fix: Apply all formatting, style, and efficiency fixes

* docs: Apply feedback and improve Javadoc

* docs: Add Hierholzer's Algorithm to DIRECTORY.md
This commit is contained in:
sharan
2025-11-02 16:06:10 +05:30
committed by GitHub
parent 08374248e9
commit d717ca4fd5
3 changed files with 201 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

60
src/test/java/com/thealgorithms/graph/HierholzerAlgorithmTest.java Normal file
View File

@@ -0,0 +1,60 @@
package com.thealgorithms.graph;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertFalse;
import static org.junit.jupiter.api.Assertions.assertTrue;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import org.junit.jupiter.api.Test;
public class HierholzerAlgorithmTest {
@Test
public void testFindsEulerianCircuitInSimpleTriangleGraph() {
Map<Integer, LinkedList<Integer>> graph = new HashMap<>();
graph.put(0, new LinkedList<>(Arrays.asList(1, 2)));
graph.put(1, new LinkedList<>(Arrays.asList(0, 2)));
graph.put(2, new LinkedList<>(Arrays.asList(0, 1)));
HierholzerAlgorithm algorithm = new HierholzerAlgorithm(graph);
assertTrue(algorithm.hasEulerianCircuit());
List<Integer> circuit = algorithm.findEulerianCircuit();
assertEquals(4, circuit.size());
assertEquals(circuit.get(0), circuit.get(circuit.size() - 1));
}
@Test
public void testFailsForGraphWithOddDegreeVertices() {
Map<Integer, LinkedList<Integer>> graph = new HashMap<>();
graph.put(0, new LinkedList<>(Collections.singletonList(1)));
graph.put(1, new LinkedList<>(Collections.singletonList(0)));
HierholzerAlgorithm algorithm = new HierholzerAlgorithm(graph);
assertFalse(algorithm.hasEulerianCircuit());
assertTrue(algorithm.findEulerianCircuit().isEmpty());
}
@Test
public void testFailsForDisconnectedGraph() {
Map<Integer, LinkedList<Integer>> graph = new HashMap<>();
graph.put(0, new LinkedList<>(Arrays.asList(1, 2)));
graph.put(1, new LinkedList<>(Arrays.asList(0, 2)));
graph.put(2, new LinkedList<>(Arrays.asList(0, 1)));
graph.put(3, new LinkedList<>(Arrays.asList(4, 5)));
graph.put(4, new LinkedList<>(Arrays.asList(3, 5)));
graph.put(5, new LinkedList<>(Arrays.asList(3, 4)));
HierholzerAlgorithm algorithm = new HierholzerAlgorithm(graph);
assertFalse(algorithm.hasEulerianCircuit());
}
@Test
public void testHandlesEmptyGraph() {
Map<Integer, LinkedList<Integer>> graph = new HashMap<>();
HierholzerAlgorithm algorithm = new HierholzerAlgorithm(graph);
assertTrue(algorithm.hasEulerianCircuit());
assertTrue(algorithm.findEulerianCircuit().isEmpty());
}
}