weightedGraph

Author: iScript

.idea/workspace.xml

@@ -0,0 +1,13 @@
+7 12
+0 1 2
+0 3 7
+0 5 2
+1 2 1
+1 3 4
+1 4 3
+1 5 5
+2 4 4
+2 5 4
+3 4 1
+3 6 5
+4 6 7

g6.txt

@@ -0,0 +1,137 @@
+import java.io.File;
+import java.io.IOException;
+import java.util.Map;
+import java.util.TreeMap;
+import java.util.Scanner;
+
+// 带权图
+public class WeightedGraph implements  Cloneable{
+
+    private int V;  // 顶点
+    private int E;  // 边
+    private TreeMap<Integer,Integer>[] adj; //adj数组，里面保存着TreeMap。treemap参数 相邻的顶点 ，权值
+
+    public WeightedGraph(String filename) {
+        File file = new File(filename);
+        if(!file.exists()) throw new IllegalArgumentException("文件不存在");
+
+        try(Scanner scanner = new Scanner(file)){
+
+            V = scanner.nextInt();  // 读取第一行的第一个，即多少个顶点
+            if(V < 0) throw new IllegalArgumentException("V must be non-negative");
+            adj = new TreeMap[V];    // 根据顶点创建数组
+
+            for(int i = 0; i < V; i ++){
+                adj[i] = new TreeMap<Integer,Integer>();    // 数组里保存着treeMap
+            }
+
+            E = scanner.nextInt();
+            if(E < 0) throw new IllegalArgumentException("E must be non-negative");
+            for(int i = 0; i < E; i ++){    //
+                int a = scanner.nextInt();validateVertex(a);
+                int b = scanner.nextInt();validateVertex(b);
+                int weight = scanner.nextInt(); //一行的第三个值是权重
+
+                if(a == b) throw new IllegalArgumentException("Self Loop is Detected!");    // 判断自环边
+                if(adj[a].containsKey(b)) throw new IllegalArgumentException("Parallel Edges are Detected!");  // 判断平行边
+
+                adj[a].put(b,weight);   // adj[x]顶点是一个TreeMap，每个顶点对应着相连的顶点和权重
+                adj[b].put(a,weight);
+            }
+        }
+        catch(IOException e){
+            e.printStackTrace();
+        }
+
+    }
+
+
+    public void validateVertex(int v){
+        if(v < 0 || v >= V)
+            throw new IllegalArgumentException("vertex " + v + "is invalid");
+    }
+
+    // 顶点
+    public int V(){
+        return V;
+    }
+
+    // 边
+    public int E(){
+        return E;
+    }
+
+    // 是否存在边
+    public boolean hasEdge(int v, int w){
+        validateVertex(v);
+        validateVertex(w);
+        return adj[v].containsKey(w);
+    }
+
+
+    // 返回v这个顶点相邻的顶点
+    public Iterable<Integer> adj(int v) {
+        validateVertex(v);
+        return adj[v].keySet();     // key是顶点、value是权重
+    }
+
+    // 返回边对应的权重
+    public int getWeight(int v,int w){
+        if(hasEdge(v,w))
+            return adj[v].get(w);
+        throw new IllegalArgumentException(String.format("no edge %d %d",v,w));
+    }
+
+    // 返回一个顶点的度，即顶点相邻的点有几个
+    public int degree(int v){
+        validateVertex(v);
+        return adj[v].size();
+    }
+
+
+//    public void removeEdge(int v,int w){
+//        validateVertex(v);
+//        validateVertex(w);
+//
+//        adj[v].remove(w);
+//        adj[w].remove(v);
+//    }
+//
+//
+//    @Override
+//    public Object clone(){
+//        try{
+//            WeightedGraph cloned = (WeightedGraph)super.clone();
+//            cloned.adj = new TreeMap[V];
+//            for(int v = 0; v < V; v ++){
+//                cloned.adj[v] = new TreeMap<Integer,Integer>();
+//                for(Map.Entry<Integer,Integer> entry : adj[v].entrySet() ) //遍历map
+//                    cloned.adj[v].put(entry.getKey(),entry.getValue());
+//            }
+//            return  cloned;
+//        }catch(CloneNotSupportedException e){
+//            e.printStackTrace();
+//        }
+//        return null;
+//    }
+////
+    @Override
+    public String toString(){
+        StringBuilder sb = new StringBuilder();
+
+        sb.append(String.format("V = %d, E = %d\n", V, E));
+        for(int i = 0; i < V; i ++){
+            sb.append(String.format("%d :", i));
+            for(Map.Entry<Integer,Integer> entry : adj[i].entrySet() ) //遍历map
+                sb.append(String.format("(%d : %d)", entry.getKey(),entry.getValue()));
+            sb.append('\n');
+        }
+        return sb.toString();
+    }
+
+    public static void main(String[] args){
+
+        WeightedGraph g = new WeightedGraph("g6.txt");
+        System.out.print(g);
+    }
+}