Add adjacency matrix activity

Author: jcazevedo

src/main/java/com/packt/datastructuresandalg/lesson6/activity/weightedundirected/AdjacencyMatrixWeightedUndirected.java

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+package com.packt.datastructuresandalg.lesson6.activity.weightedundirected;
+
+public class AdjacencyMatrixWeightedUndirected {
+    int[][] adj;
+
+    public AdjacencyMatrixWeightedUndirected(int nodes) {
+        this.adj = new int[nodes][nodes];
+    }
+
+    public void addEdge(int u, int v, int weight) { }
+
+    public int edgeWeight(int u, int v) { return 0; }
+}

src/main/java/com/packt/datastructuresandalg/lesson6/activity/weightedundirected/solution/AdjacencyMatrixWeightedUndirected.java

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+package com.packt.datastructuresandalg.lesson6.activity.weightedundirected.solution;
+
+public class AdjacencyMatrixWeightedUndirected {
+    int[][] adj;
+
+    public AdjacencyMatrixWeightedUndirected(int nodes) {
+        this.adj = new int[nodes][nodes];
+    }
+
+    public void addEdge(int u, int v, int weight) {
+        this.adj[u][v] = weight;
+        this.adj[v][u] = weight;
+    }
+
+    public int edgeWeight(int u, int v) {
+        return this.adj[u][v];
+    }
+}

src/test/java/com/packt/datastructuresandalg/lesson6/activity/weightedundirected/AdjacencyMatrixWeightedUndirectedTest.java

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+package com.packt.datastructuresandalg.lesson6.activity.weightedundirected;
+
+import junit.framework.TestCase;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+
+public class AdjacencyMatrixWeightedUndirectedTest extends TestCase {
+    public void test1() {
+        AdjacencyMatrixWeightedUndirected g = new AdjacencyMatrixWeightedUndirected(5);
+        g.addEdge(0, 1, 10);
+        g.addEdge(0, 4, 5);
+        g.addEdge(1, 2, 3);
+        g.addEdge(2, 3, 1);
+        g.addEdge(4, 3, 2);
+
+        assertTrue(g.edgeWeight(4, 0) == 5);
+        assertTrue(g.edgeWeight(0, 4) == 5);
+        assertTrue(g.edgeWeight(0, 1) == 10);
+        assertTrue(g.edgeWeight(1, 0) == 10);
+        assertTrue(g.edgeWeight(3, 4) == 2);
+        assertTrue(g.edgeWeight(1, 3) == 0);
+    }
+}