本算法是求V0到各个点的最短距离
import java.util.Arrays;
class Vertex{
int distance;//到这个点的距离
int preVertexIndex;//为了到达此点的前一个点的下标
boolean sure = false;//标志这个点是否被确定，默认未确定
public Vertex(int distance, int preVertexIndex){
this.distance = distance;
this.preVertexIndex = preVertexIndex;
}
@Override
public String toString() {
return "["+distance+","+preVertexIndex+"]";
}
}
public class Main {
//矩阵阶数
static int matrixOrder = 6;
//无穷距离
static int MD = 999;
//距离数组
static Vertex[] distance = new Vertex[matrixOrder];
//邻接矩阵
//第一行表示V0->Vi(i=0,1,2,3,4,5)的距离，其它类似
static int[][] arcs = {
{0, 50, 10, MD, 45, MD},
{MD, 0, 15, MD, 5, MD},
{20, MD, 0, 15, MD, MD},
{MD, 20, MD, 0, 35, MD},
{MD, MD, MD, 30, 0, MD},
{MD, MD, MD, 3, MD, 0 }} ;
//从距离数组中查找距离值最短的节点下标
static int findShortestDistanceVertexIndexFromDistanceArray(){
int shortestDistance = 999;
int shortestVertexIndex = matrixOrder;
for(int i = 0; i < matrixOrder; i++){
if(distance[i].sure == false && distance[i].distance <= shortestDistance){
shortestDistance = distance[i].distance;
shortestVertexIndex = i;
}
}
return shortestVertexIndex;
}
//判断是否结束
static boolean isOver(){
for(int i = 0; i < matrixOrder; i++){
if(distance[i].sure == false)
return false;
}
return true;
}
static void calculateShortestDistance(){
//初始化距离数组
for(int i = 0; i < matrixOrder; i++){
Vertex vertex;
if(arcs[0][i] != MD){
vertex = new Vertex(arcs[0][i], 0);
}else {
vertex = new Vertex(arcs[0][i], -1);
}
distance[i] = vertex;
}
while (true){
if(isOver())
break;
int shortestVertexIndex = findShortestDistanceVertexIndexFromDistanceArray();
for(int i = 0; i < matrixOrder; i++){
if(distance[i].sure)
continue;
if(distance[shortestVertexIndex].distance + arcs[shortestVertexIndex][i] < distance[i].distance){
distance[i].preVertexIndex = shortestVertexIndex;
distance[i].distance = distance[shortestVertexIndex].distance + arcs[shortestVertexIndex][i];
}
}
distance[shortestVertexIndex].sure = true;
}
}
public static void main(String[] args) {
calculateShortestDistance();
System.out.println(Arrays.toString(distance));
}
}