dijkstra算法求两点之间最短路径

http://128kj.iteye.com/blog/1678532

package com.geo.xiaojinku.udf.utils;

import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Map.Entry;

import javax.print.attribute.standard.PrinterInfo;

import org.apache.hadoop.classification.InterfaceAudience.Private;

public class FloydUtil {
private static int M = 10000; // 此路不通
private static String pathTip = "-->";
private static Map<String, Object> pathInfoMap = new LinkedHashMap<String, Object>(); // 路径和距离信息

public static void main(String[] args) {
int[][] weight1 = {
{ 0, 1, 1, 4, M, 2, 5, M },
{ 1, 0, M, M, M, 2, M, 4 },
{ 1, M, 0, M, M, M, 3, M },
{ 4, M, M, 0, 1, M, M, M },
{ M, M, M, 1, 0, 1, M, M },
{ 2, 2, M, M, 1, 0, M, M },
{ 5, M, 3, M, M, M, 0, 1 },
{ M, 4, M, M, M, M, 1, 0 }
};
String[] point = { "A", "B", "C", "D", "E", "F", "G", "H" };
for (int start = 0; start < point.length; start++) {
getPathInfo(weight1, start, point);
}
printPathInfo();

}
public static void getPathInfo(int[][] weight, int start, String[] point) {
// 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）
int n = weight.length; // 顶点个数
int[] shortPath = new int
; // 保存start到其他各点的最短路径
String[] path = new String
; // 保存start到其他各点最短路径的字符串表示
for (int i = 0; i < n; i++){
path[i] = new String(point[start] + pathTip + point[i]);
}
int[] visited = new int
; // 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，第一个顶点已经求出
shortPath[start] = 0;
visited[start] = 1;
for (int count = 1; count < n; 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 = Integer.MAX_VALUE;
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，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];
path[i] = path[k] + pathTip + point[i];
}
}
}
for (int i = 0; i < n; i++) {
// System.out.print("从" + point[start] + "出发到" + point[i] +
// "的最短路径为：" + path[i] + " ");
// System.out.println("从" + point[start] + "出发到" + point[i] +
// "的最短距离为：" + shortPath[i]);
Object[] objects = new Object[2];
objects[0] = path[i];
objects[1] = shortPath[i];
pathInfoMap.put(point[start] + pathTip + point[i], objects);
}

}
/**
* 打印路径信息和距离
*/
private static void printPathInfo() {
for (Entry<String, Object> entry : pathInfoMap.entrySet()) {
String key = entry.getKey();
Object[] objects = (Object[]) entry.getValue();
System.out.println(key + ":" + objects[0] + "  路径长度：" + objects[1]);
}
}

}