用java编写的一个迪杰斯特拉算法（单源最短路径算法，Dijkstra算法）。，单源dijkstra,package Test

用java编写的一个迪杰斯特拉算法（单源最短路径算法，Dijkstra算法）。，单源dijkstra,package Test

package Test;import java.util.TreeMap;import java.util.ArrayList;import java.io.BufferedReader;import java.io.InputStreamReader;import java.io.IOException;class Point {    private int id;// 点的id    private boolean flag = false;// 标志是否被遍历    int sum;// 记录总的点个数    private TreeMap<Integer, Integer> thisPointMap = new TreeMap<Integer, Integer>();// 该点到各点的距离。    BufferedReader bufr = new BufferedReader(new InputStreamReader(System.in));    Point(int sum) { // 构造函数 带有顶点个数        this.sum = sum;    }    public void setId(int id) {// 设置顶点id        this.id = id;    }    public int getId() {// 获得顶点id        return this.id;    }    public void changeFlag() {// 修改访问状态。        this.flag = true;    }    public boolean isVisit() {// 查看访问状态        return flag;    }    public void setLenToOther()throws IOException{// 初始化改点到各顶点的距离。        System.out.println("=======请输入顶点" + (this.id + 1) + "至其他各顶点的边距=======");        for (int i = 0; i < sum; i++) {            if (i == this.id)                thisPointMap.put(this.id, 0);            else {                System.out.print("至 顶点" + (i + 1) + " 的距离 ：");                boolean flag =true;                int len = 0;                while(flag){                    try {                        len = Integer.valueOf(bufr.readLine());                        flag = false;                    } catch (NumberFormatException e) {                        System.out.print("输入有误，请重新输入：");                    }                };                thisPointMap.put(i, len);            }        }    }    // 该点到顶尖id的 距离。    public int lenToPointId(int id) {        return thisPointMap.get(id);    }}class Dijkstra {    public static void main(String[] args)throws IOException {        ArrayList<Point> point_arr = new ArrayList<Point>();// 存储点集合        BufferedReader bufr = new BufferedReader(new InputStreamReader(System.in));        System.out.print("请输入顶点个数： ");        int sum = 0;        boolean flag =true;        while(flag){            try {                sum = Integer.valueOf(bufr.readLine());                flag = false;            } catch (NumberFormatException e) {                System.out.print("输入有误，请重新输入：");            }        };        for (int i = 0; i < sum; i++) {// 初始化            Point p = new Point(sum);            p.setId(i);            p.setLenToOther();            point_arr.add(p);        }        System.out.print("请输入起始顶点 id ：");        boolean flag2 =true;        int start = 0;        while(flag2){            try {                start = Integer.valueOf(bufr.readLine())-1;                if(start > sum-1 || start < 0)                    throw new NumberFormatException();                flag2 = false;            }catch (NumberFormatException e) {                System.out.print("输入有误，请重新输入：");            }        };        showDijkstra(point_arr, start);// 单源最短路径遍历    }    public static void showDijkstra(ArrayList<Point> arr, int i) {        System.out.print("顶点" + (i + 1));        arr.get(i).changeFlag();        Point p1 = getTopointMin(arr, arr.get(i));        if (p1 == null)            return;        int id = p1.getId();        showDijkstra(arr, id);    }    public static Point getTopointMin(ArrayList<Point> arr, Point p) {        Point temp = null;        int minLen = Integer.MAX_VALUE;        for (int i = 0; i < arr.size(); i++) {            // 当已访问 或 者是自身或者无该路径时跳过。            if (arr.get(i).isVisit() || arr.get(i).getId() == p.getId() || p.lenToPointId(i) < 0)                continue;            else {                if (p.lenToPointId(i) < minLen) {                    minLen = p.lenToPointId(i);                    temp = arr.get(i);                }            }        }        if (temp == null)            return temp;        else            System.out.print("  @--" + minLen + "--> ");        return temp;    }}{--