[FEAT] Implement Dials Algorithm (Graph) (#6679)

[FEAT] Implement Dials Algorithm(Graph) Co-authored-by: Priyanshu1303d <priyanshu130d@gmail.com>
2025-12-19 07:00:35 +08:00 · 2025-10-13 00:55:21 +05:30
parent 14a23b709a
commit 9a907c8843
2 changed files with 202 additions and 0 deletions
--- a/src/test/java/com/thealgorithms/datastructures/graphs/DialsAlgorithmTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/graphs/DialsAlgorithmTest.java
@@ -0,0 +1,88 @@
+package com.thealgorithms.datastructures.graphs;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.ArrayList;
+import java.util.List;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+final class DialsAlgorithmTest {
+
+    private List<List<DialsAlgorithm.Edge>> graph;
+    private static final int NUM_VERTICES = 6;
+    private static final int MAX_EDGE_WEIGHT = 10;
+
+    @BeforeEach
+    void setUp() {
+        graph = new ArrayList<>();
+        for (int i = 0; i < NUM_VERTICES; i++) {
+            graph.add(new ArrayList<>());
+        }
+    }
+
+    private void addEdge(int u, int v, int weight) {
+        graph.get(u).add(new DialsAlgorithm.Edge(v, weight));
+    }
+
+    @Test
+    @DisplayName("Test with a simple connected graph")
+    void testSimpleGraph() {
+        // Build graph from a standard example
+        addEdge(0, 1, 2);
+        addEdge(0, 2, 4);
+        addEdge(1, 2, 1);
+        addEdge(1, 3, 7);
+        addEdge(2, 4, 3);
+        addEdge(3, 5, 1);
+        addEdge(4, 3, 2);
+        addEdge(4, 5, 5);
+
+        int[] expectedDistances = {0, 2, 3, 8, 6, 9};
+        int[] actualDistances = DialsAlgorithm.run(graph, 0, MAX_EDGE_WEIGHT);
+        assertArrayEquals(expectedDistances, actualDistances);
+    }
+
+    @Test
+    @DisplayName("Test with a disconnected node")
+    void testDisconnectedNode() {
+        addEdge(0, 1, 5);
+        addEdge(1, 2, 5);
+        // Node 3, 4, 5 are disconnected
+
+        int[] expectedDistances = {0, 5, 10, Integer.MAX_VALUE, Integer.MAX_VALUE, Integer.MAX_VALUE};
+        int[] actualDistances = DialsAlgorithm.run(graph, 0, MAX_EDGE_WEIGHT);
+        assertArrayEquals(expectedDistances, actualDistances);
+    }
+
+    @Test
+    @DisplayName("Test with source as destination")
+    void testSourceIsDestination() {
+        addEdge(0, 1, 10);
+        int[] expectedDistances = {0, 10, Integer.MAX_VALUE, Integer.MAX_VALUE, Integer.MAX_VALUE, Integer.MAX_VALUE};
+        // Run with source 0
+        int[] actualDistances = DialsAlgorithm.run(graph, 0, MAX_EDGE_WEIGHT);
+        assertArrayEquals(expectedDistances, actualDistances);
+    }
+
+    @Test
+    @DisplayName("Test graph with multiple paths to a node")
+    void testMultiplePaths() {
+        addEdge(0, 1, 10);
+        addEdge(0, 2, 3);
+        addEdge(2, 1, 2); // Shorter path to 1 is via 2 (3+2=5)
+
+        int[] expectedDistances = {0, 5, 3, Integer.MAX_VALUE, Integer.MAX_VALUE, Integer.MAX_VALUE};
+        int[] actualDistances = DialsAlgorithm.run(graph, 0, MAX_EDGE_WEIGHT);
+        assertArrayEquals(expectedDistances, actualDistances);
+    }
+
+    @Test
+    @DisplayName("Test with an invalid source vertex")
+    void testInvalidSource() {
+        assertThrows(IllegalArgumentException.class, () -> DialsAlgorithm.run(graph, -1, MAX_EDGE_WEIGHT));
+        assertThrows(IllegalArgumentException.class, () -> DialsAlgorithm.run(graph, NUM_VERTICES, MAX_EDGE_WEIGHT));
+    }
+}