1、问题描述

如下图，存在A~F六个地点，已知所有地点的相关关系（每个地点能到达的下一节点名称以及对应的路程）；
计算某个起点（A~F）到某个终点（A~F）所需要的路程以及经过的地点顺序

2、节点类设置

public class Node {// 当前节点名称public String name;// 记录当前节点所能能到达的节点路程 节点名称：对应的路程public Map<String,Integer> map = new HashMap<String,Integer>();// 存储所有能到达节点的对象public List<Node> nodeList = new ArrayList<Node>();public Node(){}public Node(String name){this.name = name;}public void setValue(String key,Integer value) {map.put(key,value);}public void setNode(Node node) {nodeList.add(node);}
}

3、设置节点之间的关系

public static Node setRoute() {Node nodeA = new Node("A");Node nodeB = new Node("B");Node nodeC = new Node("C");Node nodeD = new Node("D");Node nodeE = new Node("E");Node nodeF = new Node("F");nodeA.setValue("B",10);nodeA.setValue("C",14);nodeA.setNode(nodeB);nodeA.setNode(nodeC);nodeB.setValue("A",10);nodeB.setValue("C",11);nodeB.setValue("D",8);nodeB.setNode(nodeA);nodeB.setNode(nodeC);nodeB.setNode(nodeD);nodeC.setValue("A",14);nodeC.setValue("B",11);nodeC.setValue("D",6);nodeC.setValue("E",15);nodeC.setNode(nodeA);nodeC.setNode(nodeB);nodeC.setNode(nodeD);nodeC.setNode(nodeE);nodeD.setValue("B",8);nodeD.setValue("C",6);nodeD.setValue("F",10);nodeD.setNode(nodeB);nodeD.setNode(nodeC);nodeD.setNode(nodeF);nodeE.setValue("C",15);nodeE.setValue("F",12);nodeE.setNode(nodeC);nodeE.setNode(nodeF);nodeF.setValue("D",10);nodeF.setValue("E",12);nodeF.setNode(nodeD);nodeF.setNode(nodeE);return nodeA; // 起点
}

4、路线规划

/*** 计算到达某个节点所有的方式* @param node      当前节点* @param stepStr   所走过的路径（避免重复）* @param steps     总路程* @param endNode   终点节点*/
public static void calculate(Node node,String stepStr,Integer steps,String endNode) {if(!node.name.equals(endNode)) {List<Node> nodeList = node.nodeList;for (int i = 0; i < nodeList.size(); i++) {Node n = nodeList.get(i);if(stepStr.contains(n.name)) { continue; }String stepStrT = stepStr + "->" + n.name;int stepsT = steps + node.map.get(n.name);calculate(n,stepStrT,stepsT,endNode);}}else {System.out.println("finish：" + steps +"\t" + stepStr);}
}

5、完整类

package Test;import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;// 路线规划
public class RoutePlanning {// 记录执行次数public static int num = 0;public static void main(String[] args) {Node route = setRoute();calculate(route,"A",0,"F");System.out.println("execute times: " + num);}/*** 计算到达某个节点所有的方式* @param node      当前节点* @param stepStr   所走过的路径（避免重复）* @param steps     总路程* @param endNode   终点节点*/public static void calculate(Node node,String stepStr,Integer steps,String endNode) {if(!node.name.equals(endNode)) {List<Node> nodeList = node.nodeList;for (int i = 0; i < nodeList.size(); i++) {++num;Node n = nodeList.get(i);if(stepStr.contains(n.name)) { continue; }String stepStrT = stepStr + "->" + n.name;int stepsT = steps + node.map.get(n.name);calculate(n,stepStrT,stepsT,endNode);}}else {System.out.println("finish：" + steps +"\t" + stepStr);}}/*** 创建节点以及设置节点信息*/public static Node setRoute() {Node nodeA = new Node("A");Node nodeB = new Node("B");Node nodeC = new Node("C");Node nodeD = new Node("D");Node nodeE = new Node("E");Node nodeF = new Node("F");nodeA.setValue("B",10);nodeA.setValue("C",14);nodeA.setNode(nodeB);nodeA.setNode(nodeC);nodeB.setValue("A",10);nodeB.setValue("C",11);nodeB.setValue("D",8);nodeB.setNode(nodeA);nodeB.setNode(nodeC);nodeB.setNode(nodeD);nodeC.setValue("A",14);nodeC.setValue("B",11);nodeC.setValue("D",6);nodeC.setValue("E",15);nodeC.setNode(nodeA);nodeC.setNode(nodeB);nodeC.setNode(nodeD);nodeC.setNode(nodeE);nodeD.setValue("B",8);nodeD.setValue("C",6);nodeD.setValue("F",10);nodeD.setNode(nodeB);nodeD.setNode(nodeC);nodeD.setNode(nodeF);nodeE.setValue("C",15);nodeE.setValue("F",12);nodeE.setNode(nodeC);nodeE.setNode(nodeF);nodeF.setValue("D",10);nodeF.setValue("E",12);nodeF.setNode(nodeD);nodeF.setNode(nodeE);return nodeA;}public static class Node {// 当前节点名称public String name;// 记录当前节点所能能到达的节点路程public Map<String,Integer> map = new HashMap<String,Integer>();// 存储所有到达的节点对象public List<Node> nodeList = new ArrayList<Node>();public Node(){}public Node(String name){this.name = name;}public void setValue(String key,Integer value) {map.put(key,value);}public void setNode(Node node) {nodeList.add(node);}}
}

6、结果

finish：37	A->B->C->D->F
finish：48	A->B->C->E->F
finish：51	A->B->D->C->E->F
finish：28	A->B->D->F
finish：43	A->C->B->D->F
finish：30	A->C->D->F
finish：41	A->C->E->F
execute times: 41

7、优化

优化：每次遍历都判断所走路程，（详细记录已走的节点）；如果当前路程超过记录中的最大路程，则停止；
选中记录列表中的最小路程重新往下走；重复该过程，直到到达终点后