1 package iYou.neugle.graph; 2 3 import java.util.ArrayList; 4 import java.util.List; 5 6 //创建图过程的代码在图的那篇博文中,此处直接使用 7 public class Dijkstra { 8 private MyGraph1 graph; 9 private int start; 10 private int maxNum; 11 private int[] distance;// 起始点到终点距离 12 private int[] point;// 除起始点的其他点的集合 13 private String[] path;// 起始点到终点的路径 14 private List<Integer> s = new ArrayList<Integer>();// 点的集合 15 16 public Dijkstra(MyGraph1 graph, int start) { 17 this.graph = graph; 18 this.start = start - 1; 19 this.maxNum = this.graph.getGraph().maxNum; 20 distance = new int[this.maxNum - 1]; 21 point = new int[this.maxNum - 1]; 22 path = new String[this.maxNum - 1]; 23 } 24 25 // 初始化最小距离数组 26 private void Init() { 27 for (int i = 0; i < this.maxNum - 1; i++) { 28 this.distance[i] = Integer.MAX_VALUE; 29 if (i >= this.start) { 30 this.point[i] = i + 1; 31 } else { 32 this.point[i] = i; 33 } 34 } 35 } 36 37 public void DijkstraCore() { 38 this.Init(); 39 // 首先将起始节点加入到集合s中 40 this.s.add(this.start); 41 // 初始化中间节点u 42 int u = this.start; 43 // 若果s集合达到maxNum则终止 44 while (s.size() < this.maxNum) { 45 int[][] edges = this.graph.getGraph().edge; 46 boolean b = false; 47 for (int i = 0; i < edges[u].length; i++) { 48 // 如果开始节点和中间节点不连通则不进行任何操作(排除开始节点) 49 if (edges[this.start][u] == 0 && u != this.start) { 50 break; 51 } 52 // 节点到起始点的距离是不用求的 53 if (i == this.start) { 54 b = true; 55 continue; 56 } 57 int x; 58 // 如果在起始节点之后的节点需要i-- 59 if (b == false) { 60 x = i; 61 } else { 62 x = i - 1; 63 } 64 // 如果有路径则计算 65 if (edges[u][i] != 0) { 66 int temp = edges[this.start][u] + edges[u][i]; 67 if (temp < this.distance[x]) { 68 this.distance[x] = temp; 69 if (this.start == u) { 70 this.path[x] = (this.start + 1) + "->" + (i + 1); 71 } else { 72 this.path[x] = (this.start + 1) + "->" + (u + 1) 73 + "->" + (i + 1); 74 } 75 } 76 } 77 } 78 // 找到下一次的中间节点 79 u = this.Function(); 80 // 将中间点加入到集合s中 81 this.s.add(u); 82 } 83 this.Print(); 84 } 85 86 // 功能函数:找到此时distance数组中的最小值(最小值的条件是不在s中的最小值) 87 private int Function() { 88 int u = Integer.MAX_VALUE; 89 int k = -1; 90 for (int i = 0; i < this.distance.length; i++) { 91 // 如果在s中存在该节点则继续找其他次小的节点 92 if (this.s.contains(this.point[i])) { 93 continue; 94 } else { 95 if (this.distance[i] < u) { 96 u = this.distance[i]; 97 k = this.point[i]; 98 } 99 } 100 } 101 return k; 102 } 103 104 // 打印结果 105 private void Print() { 106 for (int i = 0; i < this.distance.length; i++) { 107 System.out.println(this.path[i] + ":" + this.distance[i]); 108 } 109 } 110 111 public static void main(String[] args) { 112 MyGraph1 graph = new MyGraph1(5, 0); 113 graph.CreateMaxtrixGraph(1, 2, 2); 114 graph.CreateMaxtrixGraph(1, 3, 5); 115 graph.CreateMaxtrixGraph(1, 5, 3); 116 graph.CreateMaxtrixGraph(2, 4, 4); 117 graph.CreateMaxtrixGraph(3, 5, 5); 118 graph.CreateMaxtrixGraph(4, 5, 2); 119 graph.OutPutMaxtrixGraph(); 120 Dijkstra dijkstra = new Dijkstra(graph, 2); 121 dijkstra.DijkstraCore(); 122 } 123 }
1 2 3 4 5 1 0 2 5 0 3 2 2 0 0 4 0 3 5 0 0 0 5 4 0 4 0 0 2 5 3 0 5 2 0 2->1:2 2->1->3:7 2->4:4 2->1->5:5
时间: 2024-10-07 05:56:28