연결리스트를 이용한 무방향 그래프의 구현 완료

yoonexample/src/main/java/graph/Graph.java

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+package graph;
+
+/**
+ * 간단한 그래프 자료구조의 인터페이스
+ *
+ * @author dion
+ */
+public interface Graph {
+
+  /**
+   * 매개변수 fromV와 toV로 전달된 정점을 연결하는 간선을 그래프에 추가합니다.
+   *
+   * @param fromV 시작하는 정점
+   * @param toV   도달하는 정점
+   */
+  void addEdge(Enum<?> fromV, Enum<?> toV);
+
+  /**
+   * 그래프의 간선정보를 반환합니다.
+   */
+  String showGraphEdgeInfo();
+}

yoonexample/src/main/java/graph/ListGraph.java

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+package graph;
+
+import list.DummyDoublyLinkedList;
+import list.List;
+
+public class ListGraph implements Graph {
+
+  private final List<Enum<?>>[] vertexes;
+
+  public ListGraph(int vertexCount, Class<? extends Enum<?>> clazz) {
+    Enum<?>[] enumConstants = clazz.getEnumConstants();
+    int min = Math.min(vertexCount, enumConstants.length);
+
+    this.vertexes = new List[min];
+    for (int i = 0; i < min; i++) {
+      this.vertexes[i] = new DummyDoublyLinkedList<>();
+      this.vertexes[i].insert(enumConstants[i]);
+    }
+  }
+
+  @Override
+  public void addEdge(Enum<?> fromV, Enum<?> toV) {
+    vertexes[fromV.ordinal()].insert(toV);
+    vertexes[toV.ordinal()].insert(fromV);
+  }
+
+  @Override
+  public String showGraphEdgeInfo() {
+    StringBuilder sb = new StringBuilder();
+
+    for (List<Enum<?>> vertex : vertexes) {
+      if (vertex.size() > 1) {
+        for (int i = 0; i < vertex.size(); i++) {
+          sb.append(vertex.get(i));
+          if (i == 0) {
+            sb.append(": ");
+          } else if (i < vertex.size() - 1) {
+            sb.append(" ");
+          }
+        }
+        sb.append("\n");
+      }
+    }
+
+    return sb.toString();
+  }
+}

yoonexample/src/test/java/graph/GraphTest.java

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+package graph;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class GraphTest {
+
+  Graph graph;
+
+  @BeforeEach
+  void setUp() {
+    graph = new ListGraph(5, Point.class);
+  }
+
+  @Test
+  void 그래프_초기화_테스트() {
+    assertThat(graph).isNotNull();
+  }
+
+  @Test
+  void 방향_그래프_정점_연결_테스트() {
+    graph.addEdge(Point.A, Point.B);
+    assertThat(graph.showGraphEdgeInfo()).isEqualTo("A: B\nB: A\n");
+
+    graph.addEdge(Point.A, Point.D);
+    assertThat(graph.showGraphEdgeInfo()).isEqualTo("A: B D\nB: A\nD: A\n");
+
+    graph.addEdge(Point.B, Point.C);
+    assertThat(graph.showGraphEdgeInfo()).isEqualTo("A: B D\nB: A C\nC: B\nD: A\n");
+
+    graph.addEdge(Point.C, Point.D);
+    assertThat(graph.showGraphEdgeInfo()).isEqualTo("A: B D\nB: A C\nC: B D\nD: A C\n");
+
+    graph.addEdge(Point.D, Point.E);
+    assertThat(graph.showGraphEdgeInfo()).isEqualTo("A: B D\nB: A C\nC: B D\nD: A C E\nE: D\n");
+
+    graph.addEdge(Point.E, Point.A);
+    assertThat(graph.showGraphEdgeInfo()).isEqualTo("A: B D E\nB: A C\nC: B D\nD: A C E\nE: D A\n");
+  }
+
+  private enum Point {
+    A, B, C, D, E, F, G, H, I, J
+  }
+}