数据结构之最小生成树

若要在n个城市之间建设通信网络，只需要架设n-1条线路即可。如何以最低的经济待价建设这个通信网，是一个网的最小生成树问题。

#include<stdio.h>                                                                                                                                                             struct Edge{char v1;char v2;int length;};struct Headtype{Edge space[20];int Elength;};struct Dgree{char v;int flag;};struct Mark{Dgree biao[20];int Glength;};void InitMark(Mark &M,int x){int j;M.Glength=x;printf("Please input these nodes:\n");for(j=1;j<=x;j++){scanf("%s",&M.biao[j].v);M.biao[j].flag=-1;}}void InitHeadType(Headtype &H,int y){int k;H.Elength=y;for(k=1;k<=y;k++){printf("Please input relation between nodes and edges:\n");                                       scanf("%s%s%d",&H.space[k].v1,&H.space[k].v2,&H.space[k].length);        printf("%c->%c:%d\n",H.space[k].v1,H.space[k].v2,H.space[k].length);}                                                                                                                   }                                                                                                                                         void HeadAdjust(Headtype &H,int s,int m){Edge rc;int p;rc=H.space[s];for(p=2*s;p<=m;p*=2){if(p<m&&(H.space[p].length<H.space[p+1].length))++p;if(rc.length>H.space[p].length)break;H.space[s]=H.space[p];s=p;}H.space[s]=rc;}void HeadSort(Headtype &H){int q;Edge rb;for(q=H.Elength/2;q>0;--q)HeadAdjust(H,q,H.Elength);for(q=H.Elength;q>1;--q){rb=H.space[1];H.space[1]=H.space[q];H.space[q]=rb;HeadAdjust(H,1,q-1);}}void main()                                                        {                                                                  int Gnumber,Enumber,a,b,c;                                       printf("Please input nodes' number:\n");                                       scanf("%d",&Gnumber);                                              Enumber=Gnumber*(Gnumber-1)/2;Headtype H;                                                       Mark M;  Dgree e1,e2;                                                                                                  InitMark(M,Gnumber);                                                                    InitHeadType(H,Enumber);                                                             HeadSort(H);                                                   printf("The mintree is;\n");                                                                                              for(a=1;a<=Enumber;a++)                                            {                                                                 for(b=1;b<=Gnumber;b++){if(M.biao[b].v==H.space[a].v1)                                        {e1=M.biao[b];  break; }}                                               for(c=1;c<=Gnumber;c++){                                            if(M.biao[c].v==H.space[a].v2)                                        {e2=M.biao[c];  break; } }                                                                                                                                                               while(e1.flag!=-1){b=e1.flag;                                                e1=M.biao[e1.flag];}                                                  while(e2.flag!=-1){c=e2.flag;                                                 e2=M.biao[e2.flag]; }                                                 if(e2.v!=e1.v){ M.biao[b].flag=c;                                                                               printf("(%c,%c):%d\n",H.space[a].v1,H.space[a].v2,H.space[a].length);      }}                                                                  }