floyd算法

主类：

public class FloydAlgorithm {
	public static void main(String[] args) {
		char[] vertex = { ‘A‘, ‘B‘, ‘C‘, ‘D‘, ‘E‘, ‘F‘, ‘G‘ };
		int[][] matrix = new int[vertex.length][vertex.length];
		final int N = 65535;
		matrix[0] = new int[] { 0, 5, 7, N, N, N, 2 };
		matrix[1] = new int[] { 5, 0, N, 9, N, N, 3 };
		matrix[2] = new int[] { 7, N, 0, N, 8, N, N };
		matrix[3] = new int[] { N, 9, N, 0, N, 4, N };
		matrix[4] = new int[] { N, N, 8, N, 0, 5, 4 };
		matrix[5] = new int[] { N, N, N, 4, 5, 0, 6 };
		matrix[6] = new int[] { 2, 3, N, N, 4, 6, 0 };
		Graph graph = new Graph(vertex.length, matrix, vertex);
		graph.floyd();
		graph.show();
	}
}

Graph类：

class Graph{
	private char[] vertex;//存放顶点的数组
	private int[][] dis;//保存从各个顶点出发到其他顶点的距离
	private int[][] pre;//保存到达目标顶点的前驱顶点
	
    //构造器与初始化
	public Graph(int length, int[][] matrix, char[] vertex) {
		this.vertex = vertex;
		this.dis = matrix;
		this.pre = new int[length][length];
		for(int i = 0; i < length; i++) {
			Arrays.fill(pre[i], i);
		}
	}
	
    /**
    * 第一行显示各个顶点到其他顶点的前驱节点，第二行显示到达其他顶点的距离
    */
	public void show() {
		for(int k = 0; k < dis.length; k++) {
			for(int i = 0; i < dis.length; i++) {
				System.out.print(vertex[pre[k][i]] + " ");
			}
			System.out.println();
			for(int i = 0; i < dis.length; i++) {
				System.out.print(dis[k][i] + " ");
			}
			System.out.println();
		}
	}
    
	//弗洛伊德算法
	public void floyd() {
		int len = 0;//保存距离
		//对中间顶点遍历，k就是中间顶点的下标
		for(int k = 0; k < dis.length; k++) {
			//从i顶点开始出发
			for(int i = 0; i < dis.length; i++) {
				for(int j = 0; j < dis.length; j++) {
					len = dis[i][k] + dis[k][j];
					if(len < dis[i][j]) {
						dis[i][j] = len;//更新最短距离
						pre[i][j] = pre[k][j];//更新前驱顶点
					}
				}
			}
		}
	}
}

floyd算法

原文：https://www.cnblogs.com/shanaprprpr/p/14861375.html