Java/DataStructures/Graphs/MatrixGraphs.java at master · SetGeek/Java · GitHub

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publicclassMatrixGraphs {

publicstaticvoidmain(Stringargs[]) {
AdjacencyMatrixGraphgraph = newAdjacencyMatrixGraph(10);
graph.addEdge(1, 2);
graph.addEdge(1, 5);
graph.addEdge(2, 5);
graph.addEdge(1, 2);
graph.addEdge(2, 3);
graph.addEdge(3, 4);
graph.addEdge(4, 1);
graph.addEdge(2, 3);
System.out.println(graph);
	}

}

classAdjacencyMatrixGraph {
privateint_numberOfVertices;
privateint_numberOfEdges;
privateint[][] _adjacency;

staticfinalintEDGE_EXIST = 1;
staticfinalintEDGE_NONE = 0;

publicAdjacencyMatrixGraph(intgivenNumberOfVertices) {
this.setNumberOfVertices(givenNumberOfVertices);
this.setNumberOfEdges(0);
this.setAdjacency(newint[givenNumberOfVertices][givenNumberOfVertices]);
for (inti = 0; i < givenNumberOfVertices; i++) {
for (intj = 0; j < givenNumberOfVertices; j++) {
this.adjacency()[i][j] = AdjacencyMatrixGraph.EDGE_NONE;
 }
 }
	}

privatevoidsetNumberOfVertices(intnewNumberOfVertices) {
this._numberOfVertices = newNumberOfVertices;
	}

publicintnumberOfVertices() {
returnthis._numberOfVertices;
	}

privatevoidsetNumberOfEdges(intnewNumberOfEdges) {
this._numberOfEdges = newNumberOfEdges;
	}

publicintnumberOfEdges() {
returnthis._numberOfEdges;
	}

privatevoidsetAdjacency(int[][] newAdjacency) {
this._adjacency = newAdjacency;
	}

privateint[][] adjacency() {
returnthis._adjacency;
	}

privatebooleanadjacencyOfEdgeDoesExist(intfrom, intto) {
return (this.adjacency()[from][to] != AdjacencyMatrixGraph.EDGE_NONE);
	}

publicbooleanvertexDoesExist(intaVertex) {
if (aVertex >= 0 && aVertex < this.numberOfVertices()) {
returntrue;
 } else {
returnfalse;
 }
	}

publicbooleanedgeDoesExist(intfrom, intto) {
if (this.vertexDoesExist(from) && this.vertexDoesExist(to)) {
return (this.adjacencyOfEdgeDoesExist(from, to));
 }

returnfalse;
	}

/**
 * This method adds an edge to the graph between two specified
 * vertices
 *
 * @param from the data of the vertex the edge is from
 * @param to the data of the vertex the edge is going to
 * @return returns true if the edge did not exist, return false if it already did
 */
publicbooleanaddEdge(intfrom, intto) {
if (this.vertexDoesExist(from) && this.vertexDoesExist(to)) {
if (!this.adjacencyOfEdgeDoesExist(from, to)) {
this.adjacency()[from][to] = AdjacencyMatrixGraph.EDGE_EXIST;
this.adjacency()[to][from] = AdjacencyMatrixGraph.EDGE_EXIST;
this.setNumberOfEdges(this.numberOfEdges() + 1);
returntrue;
 }
 }

returnfalse;
	}

/**
 * this method removes an edge from the graph between two specified
 * vertices
 *
 * @param from the data of the vertex the edge is from
 * @param to the data of the vertex the edge is going to
 * @return returns false if the edge doesn't exist, returns true if the edge exists and is removed
 */
publicbooleanremoveEdge(intfrom, intto) {
if(!this.vertexDoesExist(from) || !this.vertexDoesExist(to)) {
if (this.adjacencyOfEdgeDoesExist(from, to)) {
this.adjacency()[from][to] = AdjacencyMatrixGraph.EDGE_NONE;
this.adjacency()[to][from] = AdjacencyMatrixGraph.EDGE_NONE;
this.setNumberOfEdges(this.numberOfEdges() - 1);
returntrue;
 }
 }
returnfalse;
	}

/**
 * this gives a list of vertices in the graph and their adjacencies
 *
 * @return returns a string describing this graph
 */
publicStringtoString() {
Strings = newString();
s = " ";
for (inti = 0; i < this.numberOfVertices(); i++) {
s = s + String.valueOf(i) + " ";
 }
s = s + " \n";

for (inti = 0; i < this.numberOfVertices(); i++) {
s = s + String.valueOf(i) + " : ";
for (intj = 0; j < this.numberOfVertices(); j++) {
s = s + String.valueOf(this._adjacency[i][j]) + " ";
 }
s = s + "\n";
 }
returns;
	}

}