java查找图中两点之间所有路径
作者:Coder_py
这篇文章主要为大家详细介绍了java查找图中两点之间所有路径,具有一定的参考价值,感兴趣的小伙伴们可以参考一下
本文实例为大家分享了java查找图中两点之间所有路径的具体代码,基于邻接表,供大家参考,具体内容如下
图类:
package graph1; import java.util.LinkedList; import graph.Graph.edgeNode; public class Graph { class EdgeNode{ int adjvex; EdgeNode nextEdge; } class VexNode{ int data; EdgeNode firstEdge; boolean isVisted; public boolean isVisted() { return isVisted; } public void setVisted(boolean isVisted) { this.isVisted = isVisted; } } VexNode[] vexsarray ; int[] visited = new int[100]; boolean[] isVisited = new boolean[100]; public void linkLast(EdgeNode target,EdgeNode node) { while (target.nextEdge!=null) { target=target.nextEdge; } target.nextEdge=node; } public int getPosition(int data) { for(int i=0;i<vexsarray.length;i++) { if (data==vexsarray[i].data) { return i; } } return -1; } public void buildGraph(int[] vexs,int[][] edges ) { int vLen = vexs.length; int eLen = edges.length; vexsarray = new VexNode[vLen]; for(int i=0;i<vLen;i++) { vexsarray[i] = new VexNode(); vexsarray[i].data = vexs[i]; vexsarray[i].firstEdge = null; } for(int i=0;i<eLen;i++) { int a = edges[i][0]; int b = edges[i][1]; int start = getPosition(a); int end = getPosition(b); EdgeNode edgeNode = new EdgeNode(); edgeNode.adjvex = end; if (vexsarray[start].firstEdge == null) { vexsarray[start].firstEdge = edgeNode; } else { linkLast(vexsarray[start].firstEdge,edgeNode); } } } public void printGraph() { for(int i=0;i<vexsarray.length;i++) { System.out.printf("%d--",vexsarray[i].data); EdgeNode node = vexsarray[i].firstEdge; while (node!=null) { System.out.printf("%d(%d)--",node.adjvex,vexsarray[node.adjvex].data); node = node.nextEdge; } System.out.println("\n"); } }
算法:
package graph1; import java.util.HashMap; import java.util.Map; import java.util.Stack; import javax.swing.plaf.synth.SynthStyle; import graph1.Graph.EdgeNode; public class FindALlPath { //代表某节点是否在stack中,避免产生回路 public Map<Integer,Boolean> states=new HashMap(); //存放放入stack中的节点 public Stack<Integer> stack=new Stack(); //打印stack中信息,即路径信息 public void printPath(){ StringBuilder sb=new StringBuilder(); for(Integer i :stack){ sb.append(i+"->"); } sb.delete(sb.length()-2,sb.length()); System.out.println(sb.toString()); } //得到x的邻接点为y的后一个邻接点位置,为-1说明没有找到 public int getNextNode(Graph graph,int x,int y){ int next_node=-1; EdgeNode edge=graph.vexsarray[x].firstEdge; if(null!=edge&&y==-1){ int n=edge.adjvex; //元素还不在stack中 if(!states.get(n)) return n; return -1; } while(null!=edge){ //节点未访问 if(edge.adjvex==y){ if(null!=edge.nextEdge){ next_node=edge.nextEdge.adjvex; if(!states.get(next_node)) return next_node; } else return -1; } edge=edge.nextEdge; } return -1; } public void visit(Graph graph,int x,int y){ //初始化所有节点在stack中的情况 for(int i=0;i<graph.vexsarray.length;i++){ states.put(i,false); } //stack top元素 int top_node; //存放当前top元素已经访问过的邻接点,若不存在则置-1,此时代表访问该top元素的第一个邻接点 int adjvex_node=-1; int next_node; stack.add(x); states.put(x,true); while(!stack.isEmpty()){ top_node=stack.peek(); //找到需要访问的节点 if(top_node==y){ //打印该路径 printPath(); adjvex_node=stack.pop(); states.put(adjvex_node,false); } else{ //访问top_node的第advex_node个邻接点 next_node=getNextNode(graph,top_node,adjvex_node); if(next_node!=-1){ stack.push(next_node); //置当前节点访问状态为已在stack中 states.put(next_node,true); //临接点重置 adjvex_node=-1; } //不存在临接点,将stack top元素退出 else{ //当前已经访问过了top_node的第adjvex_node邻接点 adjvex_node=stack.pop(); //不在stack中 states.put(adjvex_node,false); } } } } }
测试类:
package graph1; import java.util.Iterator; import graph1.Graph.VexNode; public class Tset2 { public static void main(String[] args) { int[] vexs = {0,1,2,3,4}; int[][] edges = { {0,1}, {0,3}, {1,0}, {1,2}, {2,1}, {2,3}, {2,4}, {3,0}, {3,2}, {3,4}, {4,2}, {4,3}, }; Graph graph = new Graph(); graph.buildGraph(vexs, edges); graph.printGraph(); FindALlPath findALlPath = new FindALlPath(); findALlPath.visit(graph, 4, 0); } }
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持脚本之家。