Dijkstra算法

import java.util.Arrays;

public class Num3 {

    public static void main(String[] args)
    {
        Num3 test = new Num3();
        int MAX=Integer.MAX_VALUE-10000;
        int[][] weight={
                {0,1,12,MAX,MAX,MAX},
                {MAX,0,9,3,MAX,MAX},
                {MAX,MAX,0,MAX,5,MAX},
                {4,0,13,15,MAX,MAX},
                {MAX,MAX,MAX,MAX,0,4},
                {MAX,MAX,MAX,MAX,MAX,0}
        };
        int start=0;  //选择出发点
        int[] sp = test.getShortPath(weight,start);
        System.out.println(Arrays.toString(sp));
    }

    public int[] getShortPath(int[][] weight, int start){
        int[] visit = new int[weight.length]; //标记某节点是否被访问过
        for(int i:visit) //初始标记为未访问
            visit[i]=0;
        visit[start]=1;
        for(int k=1;k<=weight.length-1;k++) //循环中每次确定一个新的确定最短路径的节点
        {
            int dmin=Integer.MAX_VALUE;
            int position=0;
            //找出一个未标记的离出发点最近的节点
            for(int i=0;i<weight.length;i++)
            {
                if(visit[i]==0&&weight[start][i]<dmin&&i!=start)
                {
                    dmin=weight[start][i];
                    position=i;
                }
            }
            System.out.println("选出一个最短的路径："+dmin+"它是位置是："+position);
            //标记该节点为已经访问过
            visit[position]=1;

            for(int i=1;i<weight.length;i++)
            {

                if(weight[start][position]+weight[position][i]<weight[start][i]&&i!=position)
                {
                    System.out.println("原先的最短路径到"+i+"距离是:"+weight[start][i]);
                    System.out.println("两者分别是"+weight[start][position]+","+weight[position][i]);
                    weight[start][i]=weight[position][i]+weight[start][position]; //更新最短路径
                    System.out.println("更新最短路径到"+i+"距离是:"+weight[start][i]);
                }
            }
        }


        int[] shortPath = new int[weight.length];
        for(int i=0;i<weight.length;i++)
            shortPath[i]=weight[0][i];
        return shortPath;

    }
}