2023.3.17周五每日博客

合作对象：粘艺凡

昨天在实现替补分dao包的编写和一些html页面后，今天实现的站点信息输出和和线路信息的查询，通过连接数据库实现了数据库内容的输出，方便更好的查询线路和查找最短路径，尝试编写了最短路径的实现，但还是存在问题，需要进一步的探索。

其中最短路径的部分算法：

public class FloydAlgorithm {
public static int MaxValue = 100000;
public static int[][] path;
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.println("请输入顶点数和边数:");
//顶点数
int vertex = input.nextInt();
//边数
int edge = input.nextInt();

int[][] matrix = new int[vertex][vertex];
//初始化邻接矩阵
for (int i = 0; i < vertex; i++) {
for (int j = 0; j < vertex; j++) {
matrix[i][j] = MaxValue;
}
}

//初始化路径数组
path = new int[matrix.length][matrix.length];

//初始化边权值
for (int i = 0; i < edge; i++) {
System.out.println("请输入第" + (i + 1) + "条边与其权值:");
int source = input.nextInt();
int target = input.nextInt();
int weight = input.nextInt();
matrix[source][target] = weight;
}

//调用算法计算最短路径
floyd(matrix);
}

//非递归实现
public static void floyd(int[][] matrix) {
for (int i = 0; i < matrix.length; i++) {
for (int j = 0; j < matrix.length; j++) {
path[i][j] = -1;
}
}

for (int m = 0; m < matrix.length; m++) {
for (int i = 0; i < matrix.length; i++) {
for (int j = 0; j < matrix.length; j++) {
if (matrix[i][m] + matrix[m][j] < matrix[i][j]) {
matrix[i][j] = matrix[i][m] + matrix[m][j];
//记录经由哪个点到达
path[i][j] = m;
}
}
}
}

for (int i = 0; i < matrix.length; i++) {
for (int j = 0; j < matrix.length; j++) {
if (i != j) {
if (matrix[i][j] == MaxValue) {
System.out.println(i + "到" + j + "不可达");
} else {
System.out.print(i + "到" + j + "的最短路径长度是：" + matrix[i][j]);
System.out.print("最短路径为：" + i + "->");
findPath(i, j);
System.out.println(j);
}
}
}
}
}

//递归寻找路径
public static void findPath(int i, int j) {
int m = path[i][j];
if (m == -1) {
return;
}

findPath(i, m);
System.out.print(m + "->");
findPath(m, j);
}