Prime算法生成最小生成树

虽说是生成树，但我只将生成的边输出了。至于怎么用这些边来创建树。。。我不知道_(:з」∠)_ 

 

 1 //Prime方法生成最小生成树
 2 void GraphAdjacencyListWeight::GenerateMSCPPrime(int FirstVertex) {
 3     int *visited = new int[VertexNumber];
 4     memset(visited, 0, VertexNumber * sizeof(int));
 5     //-1代表没用到
 6     //0代表此点已放进容器
 7     CLOSEEDGE *CloseEdge = new CLOSEEDGE[VertexNumber];
 8     for (int lop = 0; lop < VertexNumber; lop++) {
 9         CloseEdge[lop].Weight = -1;
10         CloseEdge[lop].StartVer = -1;
11     }
12 
13     CloseEdge[FirstVertex].StartVer = 0;
14     CloseEdge[FirstVertex].Weight = 0;
15     //起点放进容器
16     visited[FirstVertex] = 1;
17 
18     //将起点的邻接信息放入CloseEdge
19     for (auto tmpPtr = (VectorVertexList[FirstVertex])->firstArc; tmpPtr != nullptr; tmpPtr = tmpPtr->nextArc) {
20         CloseEdge[tmpPtr->AdjacencyNode].StartVer = FirstVertex;
21         CloseEdge[tmpPtr->AdjacencyNode].Weight = tmpPtr->weight;
22     }
23 
24     int k = -1;
25     while (!IsAllVisited(visited)) {
26         k = SearchMinWeight(CloseEdge);
27         //输出生成的边
28         cout << "(" << CloseEdge[k].StartVer << " , " << VectorVertexList[k]->VertexIndex << ")" << endl;
29         visited[k] = 1;
30 
31         UpdateCloseEdge(CloseEdge, k);
32     }
33 
34     //销毁
35     delete[]visited;
36     delete[]CloseEdge;
37 }

Prime

 

 1 int GraphAdjacencyListWeight::SearchMinWeight(CLOSEEDGE closeedge[]) {
 2     int miniWeight = -1;
 3     int index = -1;
 4     for (int lop = 0; lop < VertexNumber; lop++) {
 5         if ((miniWeight > closeedge[lop].Weight || miniWeight == -1) && closeedge[lop].Weight > 0) {
 6             miniWeight = closeedge[lop].Weight;
 7             index = lop;
 8         }
 9     }
10     if (index == -1) {
11         //返回 -1 说明所有点都取了
12         return -1;
13     }
14     return index;
15 }
16 
17 void GraphAdjacencyListWeight::UpdateCloseEdge(CLOSEEDGE CE[], int k) {
18     //k点已被收录
19     CE[k].Weight = 0;
20     CE[k].StartVer = 0;
21 
22     for (auto tmpPtr = VectorVertexList[k]->firstArc; tmpPtr != nullptr; tmpPtr = tmpPtr->nextArc) {
23         //已是最小生成树的成员,不进行比较
24         if (CE[tmpPtr->AdjacencyNode].Weight == 0) {
25             continue;
26         }
27         if (CE[tmpPtr->AdjacencyNode].Weight >= tmpPtr->weight || CE[tmpPtr->AdjacencyNode].Weight == -1) {
28             CE[tmpPtr->AdjacencyNode].StartVer = k;
29             CE[tmpPtr->AdjacencyNode].Weight = tmpPtr->weight;
30         }
31     }
32 }

Related Functions

 

 

运行结果:

参照书本的174页的那个图