Dijkstra算法

public class Dijkstra {
 
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int[][] weight = {
                {0,3,9999999,7,9999999},
                {3,0,4,2,9999999},
                {9999999,4,0,5,6},
                {7,2,5,0,4},
                {9999999,9999999,6,4,0}
        };
         
        int[] path = Dijsktra(weight,0);
        for(int i = 0;i < path.length;i++)
            System.out.print(path[i] + "  ");
    }
     
 
    public static int[] Dijsktra(int[][] weight,int start){
        //接受一个有向图的权重矩阵，和一个起点编号start（从0编号，顶点存在数组中）
        //返回一个int[] 数组，表示从start到它的最短路径长度
        int n = weight.length;        //顶点个数
        int[] shortPath = new int[n];    //存放从start到其他各点的最短路径
        int[] visited = new int[n];        //标记当前该顶点的最短路径是否已经求出,1表示已求出
         
        //初始化，第一个顶点求出
        shortPath[start] = 0;
        visited[start] = 1;
         
        for(int count = 1;count <= n - 1;count++)        //要加入n-1个顶点
        {
            int k = -1;    //选出一个距离初始顶点start最近的未标记顶点
            int dmin = 1000;
            for(int i = 0;i < n;i++)
            {
                if(visited[i] == 0 && weight[start][i] < dmin)
                {
                    dmin = weight[start][i];
                    k = i;
                }    
            }
             
            //将新选出的顶点标记为已求出最短路径，且到start的最短路径就是dmin
            shortPath[k] = dmin;
            visited[k] = 1;
             
            //以k为中间点想，修正从start到未访问各点的距离
            for(int i = 0;i < n;i++)
            {
                if(visited[i] == 0 && weight[start][k] + weight[k][i] < weight[start][i])
                     weight[start][i] = weight[start][k] + weight[k][i];
            }    
     
        }
         
        return shortPath;
    }
}