HDU Today&&http://acm.hdu.edu.cn/showproblem.php?pid=2112

#include<iostream>
#include<string.h>
#include<string>
#include<map>
#include<algorithm>
#define N   155
#define MAX 99999999
using namespace std;
int Map

;
map<string,int>Q;
int main()
{
int n;
while(~scanf("%d",&n))
{
if(n==-1) break;
for(int i=0;i<N;++i)
for(int j=0;j<N;++j)
Map[i][j]=(i==j)?0:MAX;
string s,s1;
cin>>s>>s1;
Q.clear();
int k=0,a;
bool flag=false;
map<string,int>::const_iterator it;
Q.insert(pair<string,int>(s,++k));
if(s1!=s) Q.insert(pair<string,int>(s1,++k));
else  flag=true;
for(int i=0;i!=n;++i)
{
cin>>s>>s1>>a;
if(!flag)
{
int b,c;
it=Q.find(s);
if(it!=Q.end()) b=it->second;
else  Q.insert(pair<string,int>(s,++k)),b=k;
it=Q.find(s1);
if(it!=Q.end()) c=it->second;
else Q.insert(pair<string,int>(s1,++k)),c=k;
if(Map[b][c]>a) Map[b][c]=Map[c][b]=a;
}
}
if(flag) {printf("0\n");continue;}
for(int i=1;i<=k;++i)
for(int j=1;j<=k;++j)
for(int t=1;t<=k;++t)
if(Map[j][i]!=MAX&&Map[i][t]!=MAX&&Map[j][i]+Map[i][t]<Map[j][t])
Map[j][t]=Map[j][i]+Map[i][t];
if(Map[1][2]!=MAX) printf("%d\n",Map[1][2]);
else  printf("-1\n");
}return 0;
}

#include<iostream>
#include<string.h>
#include<cstdio>
#include<string>
#include<map>
#include<algorithm>
#include<queue>
#define N 160
#define M  40005
#define MAX 99999999
using namespace std;
typedef pair<int,int>pii;
map<string,int>Map;
void in(int &a)
{
char ch;
while((ch=getchar())<'0'||ch>'9');
for(a=0;ch>='0'&&ch<='9';ch=getchar()) a=a*10+ch-'0';
}
typedef struct node
{
int num;
int len;
int Next;
friend bool operator<(node a,node b)
{return a.len>b.len;}
}Node;
Node s[M];
int head
,res,dis
,ans,n;
int MAP

;
void init()
{
res=0,ans=0;
memset(head,-1,sizeof(head));
for(int i=0;i<N;++i)
for(int j=0;j<N;++j)
MAP[i][j]=(i==j)?0:MAX;
}
void add(int a,int b,int c)
{
s[res].num=b,s[res].len=c,s[res].Next=head[a],head[a]=res++;
}
void Djistra()
{
priority_queue<pii,vector<pii>,greater<pii> >Q;
for(int i=1;i<=ans;++i) dis[i]=(i==1)?0:MAX;
Q.push(make_pair(dis[1],1));
while(!Q.empty())
{
pii u=Q.top();
Q.pop();
int v=u.second;
if(u.first!=dis[v]) continue;
for(int i=head[v];i!=-1;i=s[i].Next)
{
if(dis[s[i].num]>dis[v]+s[i].len)
{
dis[s[i].num]=dis[v]+s[i].len;
Q.push(make_pair(dis[s[i].num],s[i].num));
}
}
}
}
int main()
{
while(~scanf("%d",&n))
{
if(n==-1) break;
init();
Map.clear();
string s,s1;
cin>>s>>s1;
bool flag=false;
Map.insert(pair<string,int>(s,++ans));
if(s!=s1) Map.insert(pair<string,int>(s1,++ans));
else flag=true;
map<string,int>::const_iterator it;
for(int i=0;i!=n;++i)
{
string s,s1;
int a,b,c;
cin>>s>>s1;
in(c);
if(!flag)
{
it=Map.find(s);
if(it!=Map.end()) a=it->second;
else  Map.insert(pair<string,int>(s,++ans)),a=ans;
it=Map.find(s1);
if(it!=Map.end()) b=it->second;
else  Map.insert(pair<string,int>(s1,++ans)),b=ans;
if(MAP[a][b]>c)  MAP[a][b]=MAP[b][a]=c;
}
}
if(flag) {printf("0\n");continue;}
for(int i=1;i<=ans;++i)
for(int j=1;j<=ans;++j)
if(i!=j)
{
if(MAP[i][j]<MAX) add(i,j,MAP[i][j]);
}
Djistra();
if(dis[2]==MAX) printf("-1\n");
else printf("%d\n",dis[2]);
}return 0;
}