HDU - 1301 Jungle Roads

https://vjudge.net/problem/HDU-1301

将村庄代号转化为数字，prim就行，注意双向存图

#include<iostream>
#include<algorithm>
#include<cstring>
using namespace std;
const int N=31;
int n;
int dis[N],g[N][N];
bool bk[N];
int prim()
{
	memset(bk,false ,sizeof bk);
	memset(dis,0x3f,sizeof dis);
	int ans=0;
	for(int i=0;i<n;i++)
	{
		int t=-1;
		for(int j=1;j<=n;j++)
		{
			if(!bk[j] && (t==-1 || dis[t]>dis[j]))
				t=j;
		}
		bk[t]=true;
		if(i) ans+=dis[t];
		for(int j=1;j<=n;j++)
			if(dis[j]>g[t][j])
				dis[j]=g[t][j]; 
	}
	return ans;
}
int main()
{
	while(cin>>n)
	{
		if(n==0) break;
		memset(g,0x3f,sizeof g);
		int t,a,b,c;
		string s,ss;
		for(int i=1;i<=n-1;i++)
		{
			cin>>s>>t;
			a=s[0]-'A'+1;
//			cout<<a<<" "<<t<<endl;
			for(int j=1;j<=t;j++)
			{
				cin>>ss>>c;
				b=ss[0]-'A'+1;
//				cout<<b<<" "<<c<<endl;
				if(g[a][b]>c)
					g[a][b]=c;
				g[b][a]=g[a][b];
			}
		}
		
		 t=prim();
		cout<<t<<"\n";
	}
	return 0;
}