void SetUnion(SetType S[],ElementType X1,ElementType X2)
{
int Root1,Root2;
Root1 = SetFind(S,X1);
Root2 = SetFind(S,X2);
if(Root1 != Root2){
if(S[Root1].parent < S[Root2].parent ){/*集合1 > 集合2*/
S[Root1].parent += S[Root2].parent;
S[Root2].parent = Root1;
}
else{
S[Root2].parent += S[Root1].parent;
S[Root1].parent = Root2;
}
}
}
void KruskalALG(ALGraph * G){
char v;
int i,j,k,parent1,parent2,EdgeNum;
EdgeNode * edge;
SetType S[G->n];
MinHeap H;
H = (MinHeap)CreateMinHeap();
int Visited[G->n];
// Initialization
for(i=0; i<G->n; i++){
S[i].Data = G->Adjlist[i].Vertex; //将所有的顶点存入生成树的集合
S[i].Parent = -1; //一开始所有顶点都是一棵独立的树
Visited[i] = FALSE;
edge = G->Adjlist[i].FirstEdge;
while( edge ){ //将所有的边组成一个最小堆（越上面的元素值越小）
MinHeapInsert(H,edge);
edge = edge->Next;
}
}
EdgeNum = 0;
while( EdgeNum < (G->n) || !IsEmptyMin(H) ){
//为什么不是找到n-1条边就停下：因为按目前的写法边数的增加次数和点的输出次数保持一致
//要输出n个点，EdgeNum就必须++ n次【需改进】
edge = (EdgeNode*)DeleteMin(H);
parent1 = SetFind(S,G->n,edge->Vertex);
parent2 = SetFind(S,G->n,edge->AdjV);
if( parent1!=parent2 || parent1==-1 ){
if( !Visited[edge->Vertex] ) {
printf("Visited Vertex : %c \n",S[edge->Vertex]);
Visited[edge->Vertex] = TRUE;
EdgeNum++;
}
if( !Visited[edge->AdjV] ) {
printf("Visited Vertex : %c \n",S[edge->AdjV]);
Visited[edge->AdjV] = TRUE;
EdgeNum++;
}
SetUnion(S,G->n,edge->Vertex,edge->AdjV);
}
}
if( EdgeNum < G->n ) printf("图不连通\n");
return ;
}
static int SetFind(int set,int label,int dest){
if (set!=EMPTY_SET) {
if (setless(label,dest,setnodes[set].label,setnodes[set].dest)) {
return SetBuild(SetFind(setnodes[set].parent,label,dest),setnodes[set].label,setnodes[set].dest);
}
if (seteq(label,dest,setnodes[set].label,setnodes[set].dest)) {
return set;
}
}
return SetBuild(set,label,dest);
}
SetName SetFind(SetType S[],ElementType X)
{
int i;
for(i=0;i<MAXN;i++){
if(S[i].Data == X)
break;
}
if(S[i].parent < 0)
return i;
else
return S[i].parent = SetFind(S,S[S[i].parent].Data);
}
/* Print a set */
PRIVATE void SetPrint(FILE *out, char *set, struct lmno *lmnop)
{
int i;
char *spacer;
spacer = "";
fprintf(out,"%12s[","");
for(i=0; i<lmnop->nterminal; i++)
{
if(SetFind(set,i))
{
fprintf(out,"%s%s",spacer,lmnop->symbols[i]->name);
spacer = " ";
}
}
fprintf(out,"]\n");
}
int SetInsert(int set,int label,int dest){
int i,hc,s;
hc=sethashcode(set,label,dest) & sethashmask;
for(i=sethash[hc];i!=EMPTY_LIST;i=setbuckets[i].next){
if (setbuckets[i].set==set&&setbuckets[i].label==label&&setbuckets[i].dest==dest) return setbuckets[i].bigset;
}
s=SetFind(set,label,dest);
if (setnodes[s].parent!=set) {
setcheckbucket();
hc=sethashcode(set,label,dest) & sethashmask;
setbuckets[setbucketnext].set=set;
setbuckets[setbucketnext].label=label;
setbuckets[setbucketnext].dest=dest;
setbuckets[setbucketnext].bigset=s;
setbuckets[setbucketnext].next=sethash[hc];
sethash[hc]=setbucketnext;
setbucketnext++;
}
return s;
}
