55import java .util .ArrayList ;
66import java .util .LinkedList ;
77
8+ /**
9+ * Implementation of a graph in a matrix form
10+ * Also known as an adjacency matrix representation
11+ * [Adjacency matrix - Wikipedia](https://en.wikipedia.org/wiki/Adjacency_matrix)
12+ *
13+ * @author Unknown
14+ */
815public class MatrixGraphs {
916
1017public static void main (String args []) {
@@ -31,14 +38,35 @@ public static void main(String args[]) {
3138 }
3239}
3340
41+ /**
42+ * AdjacencyMatrixGraph Implementation
43+ */
3444class AdjacencyMatrixGraph {
45+ /**
46+ * The number of vertices in the graph
47+ */
3548private int _numberOfVertices ;
49+
50+ /**
51+ * The number of edges in the graph
52+ */
3653private int _numberOfEdges ;
54+
55+ /**
56+ * The adjacency matrix for the graph
57+ */
3758private int [][]_adjacency ;
3859
60+ /**
61+ * Static variables to define whether or not an edge exists in the
62+ * adjacency matrix
63+ */
3964static final int EDGE_EXIST =1 ;
4065static final int EDGE_NONE =0 ;
4166
67+ /**
68+ * Constructor
69+ */
4270public AdjacencyMatrixGraph (int givenNumberOfVertices ) {
4371this .setNumberOfVertices (givenNumberOfVertices );
4472this .setNumberOfEdges (0 );
@@ -50,34 +78,77 @@ public AdjacencyMatrixGraph(int givenNumberOfVertices) {
5078 }
5179 }
5280
81+ /**
82+ * Updates the number of vertices in the graph
83+ *
84+ * @param newNumberOfVertices the new number of vertices
85+ */
5386private void setNumberOfVertices (int newNumberOfVertices ) {
5487this ._numberOfVertices =newNumberOfVertices ;
5588 }
5689
90+ /**
91+ * Getter for `this._numberOfVertices`
92+ *
93+ * @return the number of vertices in the graph
94+ */
5795public int numberOfVertices () {
5896return this ._numberOfVertices ;
5997 }
6098
99+ /**
100+ * Updates the number of edges in the graph
101+ *
102+ * @param newNumberOfEdges
103+ * */
61104private void setNumberOfEdges (int newNumberOfEdges ) {
62105this ._numberOfEdges =newNumberOfEdges ;
63106 }
64107
108+ /**
109+ * Getter for `this._numberOfEdges`
110+ *
111+ * @return the number of edges
112+ */
65113public int numberOfEdges () {
66114return this ._numberOfEdges ;
67115 }
68116
117+ /**
118+ * Sets a new matrix as the adjacency matrix
119+ *
120+ * @param newAdjacency the new adjaceny matrix
121+ */
69122private void setAdjacency (int [][]newAdjacency ) {
70123this ._adjacency =newAdjacency ;
71124 }
72125
126+ /**
127+ * Getter for the adjacency matrix
128+ *
129+ * @return the adjacency matrix
130+ */
73131private int [][]adjacency () {
74132return this ._adjacency ;
75133 }
76134
135+ /**
136+ * Checks if two vertices are connected by an edge
137+ *
138+ * @param from the parent vertex to check for adjacency
139+ * @param to the child vertex to check for adjacency
140+ * @return whether or not the vertices are adjancent
141+ */
77142private boolean adjacencyOfEdgeDoesExist (int from ,int to ) {
78143return (this .adjacency ()[from ][to ] !=AdjacencyMatrixGraph .EDGE_NONE );
79144 }
80145
146+ /**
147+ * Checks if a particular vertex exists in a graph
148+ *
149+ * @param aVertex the vertex to check for existence
150+ * @return whether or not the vertex exists
151+ */
81152public boolean vertexDoesExist (int aVertex ) {
82153if (aVertex >=0 &&aVertex <this .numberOfVertices ()) {
83154return true ;
@@ -86,6 +157,13 @@ public boolean vertexDoesExist(int aVertex) {
86157 }
87158 }
88159
160+ /**
161+ * Checks if two vertices are connected by an edge
162+ *
163+ * @param from the parent vertex to check for adjacency
164+ * @param to the child vertex to check for adjacency
165+ * @return whether or not the vertices are adjancent
166+ */
89167public boolean edgeDoesExist (int from ,int to ) {
90168if (this .vertexDoesExist (from ) &&this .vertexDoesExist (to )) {
91169return (this .adjacencyOfEdgeDoesExist (from ,to ));