水题
#include<iostream>
#include<cstring>
#include<cstdlib>
#include<cstdio>
#include<cmath>
#include<string>
#include<map>
#include<set>
#include<algorithm>
#include<vector>
#include<queue>
#include<stack>
#include<sstream>
#define LL long long
#define OJ_DEBUG 0
#define READ_FILE 0
using namespace std;
const int NN_MAX = 510;
const int MM_MAX = 100010;
const int INF = 0x1fffffff;
/**********************************************************/
int n,cnt;
int maps[NN_MAX][NN_MAX],minCost[NN_MAX];
bool vis[NN_MAX];
/**********************************************************/
int min_2 (int x,int y) {return x<y?x:y;}
int max_2 (int x,int y) {return x>y?x:y;}
void prim();
/**********************************************************/
int main()
{
if (READ_FILE) freopen ("in.txt","r",stdin);
while(scanf("%d",&n) && n)
{
int m,k;
for(int i=0;i<=n;i++)
for(int j=i;j<=n;j++)
maps[i][j]=maps[j][i]=(i==j?0:INF);
for(int i=1;i<n;i++)
{
char tmp[2];
int x,y;
scanf("%s %d",tmp,&m);
x=tmp[0]-'A'+1;
for(int j=0;j<m;j++){
scanf("%s %d",tmp,&k);
y=tmp[0]-'A'+1;
maps[x][y]=maps[y][x]=k;
}
}
cnt=0;
prim();
printf("%d\n",cnt);
}
return 0;
}
void prim()
{
memset(vis,0,sizeof(vis));
for(int i=0;i<=n;i++) minCost[i]=INF;//minCost是从已选的点集出发,到未选点距离最小权值
minCost[1]=0;
for(int i=1;i<=n;i++){//循环n次
int x=0;
for(int j=1;j<=n;j++)
if(!vis[j] && minCost[j]<minCost[x]) x=j;//找到未选点,且权值最小
vis[x]=1;
cnt+=minCost[x];
for(int j=1;j<=n;j++)
if(!vis[j])
minCost[j]=min_2(minCost[j],maps[x][j]);//从x出发,更新未选点的最小权值
}
}
#include<iostream>
#include<cstring>
#include<cstdlib>
#include<cstdio>
#include<cmath>
#include<string>
#include<map>
#include<set>
#include<algorithm>
#include<vector>
#include<queue>
#include<stack>
#include<sstream>
#define LL long long
#define OJ_DEBUG 0
#define READ_FILE 1
using namespace std;
const int NN_MAX = 510;
const int MM_MAX = 100010;
const int INF = 0x1fffffff;
struct Edge{
int a,b,c;
Edge (int a1=0,int b1=0,int c1=0):a(a1),b(b1),c(c1){}
bool operator < (const Edge& chs)const{return c<chs.c;}
}theEdge[NN_MAX*NN_MAX];
/**********************************************************/
int n,cnt,lenEdge;
int p[NN_MAX*NN_MAX];
/**********************************************************/
int min_2 (int x,int y) {return x<y?x:y;}
int max_2 (int x,int y) {return x>y?x:y;}
int find(int i) {return i==p[i]?i:p[i]=find(p[i]);}
bool merge(int i,int j)
{
int x=find(i),y=find(j);
if(x==y) return false;
p[x]=y;
return true;
}
void kruskal();
/**********************************************************/
int main()
{
if (READ_FILE) freopen ("in.txt","r",stdin);
while(scanf("%d",&n) && n)
{
int m,k;
lenEdge=0;
for(int i=1;i<n;i++)
{
char tmp[2];
int x,y;
scanf("%s %d",tmp,&m);
x=tmp[0]-'A'+1;
for(int j=0;j<m;j++){
scanf("%s %d",tmp,&k);
y=tmp[0]-'A'+1;
theEdge[lenEdge++]=Edge(x,y,k);
}
}
cnt=0;
kruskal();
printf("%d\n",cnt);
}
return 0;
}
void kruskal()
{
for(int i=0;i<=n;i++) p[i]=i;
sort(theEdge,theEdge+lenEdge);
for(int i=0;i<lenEdge;i++)
if(merge(theEdge[i].a,theEdge[i].b))
cnt+=theEdge[i].c;
}