2112HDU Today(Dijkstra)

#include <iostream>
#include <algorithm>
#include <cstring>
#include <vector>
#include <string>
#include <map>
#include <queue>
using namespace std;
#ifndef ONLINE_JUDGE
#include <fstream>
ifstream fin("test.txt");
#define cin fin
#endif
const int INF = 1000000;
int graph[200][200];
map <string, int> m;
int d[200],vis[200];
int main()
{
    ios::sync_with_stdio(false);
    int i,t,num,j;
    string a,b;
    int n;
    while(cin >> n)
    {
        if(n == -1)
        break;
        m.clear();
        memset(graph,INF,sizeof(graph));
        cin >> a >> b;
        int ok = 1;
        if(a == b)
        {
            ok = 0;
        }
        m[a] = 1;     
        m[b] = 2;
        num = 3;
        for(i = 0; i < n; ++i)
        {
            cin >> a >> b >> t;
            if(!m[a])
            m[a] = num++;
            if(!m[b])
            m[b] = num++;
            if(t < graph[m[a]][m[b]])
            graph[m[a]][m[b]] = graph[m[b]][m[a]] = t;
        }
        memset(vis,0,sizeof(vis));
        for(i = 1; i <= num; ++i)
        d[i] = (i == 1) ? 0 : INF;
        for(i = 1; i <= num; ++i)
        {
            int MIN = INF,x = 1;
            for(int y = 1; y <= num; ++y)
            if(!vis[y] && d[y] < MIN)
            MIN = d[x=y];
            vis[x] = 1;
            for(int y = 1; y <= num; ++y)
            d[y] = min(d[y],d[x]+graph[x][y]);
        }
        if(ok == 0)
        {
            cout << 0 << endl;
            continue;
        }
        if(d[2]!=INF)
        cout << d[2] << endl;
        else
        cout << -1 << endl;
    }
    return 0;
}