出差问题：
1、共有6个城市，某员工现从5号城市，到endCity出差；
2、如果一个城市遇上大雾，则该城市（既不能到达，也不能离开）；
3、给定距离矩阵useHours[][6] = {
0,2,10,5,3,INF,
INF,0,12,INF,INF,10,
INF,INF,0,INF,7,INF,
2,INF,INF,0,2,INF,
4,INF,INF,1,0,INF,
3,INF,1,INF,2,0,};
其中单位为小时，INF为1000小时
4、输入：目的地和大雾城市；
5、输出最短路径长度和路径，无法到达输出-1；
实例：
输入：
2
4
输出：
6
[5 1 2]
java编程
import java.util.*;
public class Main {
private static int INF = 1000;
private static Integer[][] dist;
private static Integer[][] path;
private static List<Integer> result = new ArrayList<Integer>();
//调试
public static void printMatrix(Integer[][] matrix) {
for (int i = 0; i < matrix.length; i++) {
for (int j = 0; j < matrix.length; j++)
System.out.print(matrix[i][j] + " ");
System.out.println();
}
}
//设置雾城市
private static void setFog(int[][] matrix, int city) {
for (int i = 0; i < matrix.length; i++) {
matrix[i][city] = matrix[city][i] = INF;
}
}
public static void main(String[] args) {
int size = 6;
int begin = 4;
Scanner scan = new Scanner(System.in);
int end = Integer.parseInt(scan.nextLine()) - 1;
int foggy = Integer.parseInt(scan.nextLine()) - 1;
scan.close();
int[][] matrix = { { 0, 2, 10, 5, 3, INF },
{ INF, 0, 12, INF, INF, 10 }, { INF, INF, 0, INF, 7, INF },
{ 2, INF, INF, 0, 2, INF }, { 4, INF, INF, 1, 0, INF },
{ 3, INF, 1, INF, 2, 0 } };
init(size);
//没有雾
if (foggy != -1)
setFog(matrix, foggy);
//调用弗洛伊德
floyd(matrix);
findPath(begin, end);
System.out.println(dist[begin][end]);
for (int i = 0; i < result.size(); i++)
result.set(i, result.get(i) + 1);
if (dist[begin][end] == INF)
result.removeAll(result);
System.out.println(result);
}
//在path数组里找路径
public static void findPath(int i, int j) {
int ci = i, ccj = j;
while (path[i][j] != -1) {
int cj = path[i][j];
result.add(cj);
i = cj;
}
result.add(0, ci);
result.add(ccj);
}
public static void floyd(int[][] matrix) {
int size = matrix.length;
for (int i = 0; i < size; i++)
for (int j = 0; j < size; j++) {
path[i][j] = -1;
dist[i][j] = matrix[i][j];
}
for (int k = 0; k < size; k++) {
for (int i = 0; i < size; i++) {
for (int j = 0; j < size; j++) {
if (dist[i][k] != INF && dist[k][j] != INF
&& dist[i][k] + dist[k][j] < dist[i][j]) {
dist[i][j] = dist[i][k] + dist[k][j];
path[i][j] = k;
}
}
}
}
}
//初始化两个数组
public static void init(int size) {
path = new Integer[size][size];
dist = new Integer[size][size];
}
}