'修改'

Author: tianqing.liang

25-GraphBascis/AdjMatrix.dart

@@ -21,16 +21,51 @@ class AdjMatrix {
   AdjMatrix( V,E,List list) {
     _V = V;
     _E = E ;
-
+    if(V < 0) throw Exception("V must be non-negative");
+    if(E < 0) throw Exception("E must be non-negative");
     _adj = List.generate(V, (_)=>List.generate(V,(_)=> 0),growable: false);
     for(int i =1;i<E;i++){
       int a =  int.parse(list[i].split(" ")[0]);
+      _validateVertex(a);
       int b = int.parse(list[i].split(" ")[1]);
+      _validateVertex(b);
       _adj![a][b] = 1;
       _adj![b][a] = 1;
     }
   }
 
+  _validateVertex(int v){
+    if(v < 0 || v >= _V!)
+      throw new Exception("vertex  $v is invalid");
+  }
+
+  int? V(){
+    return _V;
+  }
+
+  bool hasEdge(int v, int w){
+    _validateVertex(v);
+    _validateVertex(w);
+    return _adj![v][w] == 1;
+  }
+
+  int _degree(int v){
+    return _adj![v].length;
+  }
+
+  int? E(){
+    return _E;
+  }
+
+  List<int> adj(int v){
+    _validateVertex(v);
+    List<int> res = List.filled(_V!, 0,growable: true);
+    for(int i = 0; i < _V!; i ++)
+      if(_adj![v][i] == 1)
+        res.add(i);
+    return res;
+  }
+
   @override
   String toString() {
     StringBuffer sb = new StringBuffer();

README.md

@@ -36,3 +36,4 @@
 #### SDK版本
 1. 版本：2.12.3
 2. Java版本课程地址：[慕课网算法与数据结构](https://class.imooc.com/sale/datastructure)
+3. Java版本图课程：[慕课网图论算法](https://coding.imooc.com/class/370.html)