小白 stl map

#include <iostream>
#include <map>
#include <vector>
#include <string>
#include <algorithm>
#include <queue>
using namespace std;
#define INF 0x7f7f7f7f
int N, cnt, beg, end, v;
int g[155][155], res[155];    
char s[33], e[33]; 
map <string, int> mp;
struct Bus {
    int pos, val;
    Bus ( int x = 0, int y = 0 ) { pos=x, val=y; }
    bool operator < ( const Bus &t ) const {
        return val > t.val;    
    }    
};
int getId ( char *p ) {
    if ( mp.count ( p ) == 0 ) {
        return mp[p] = cnt ++;
    }    return mp[p];
}
void init () {
    mp.clear ();    cnt = 1;
    memset ( g, 0x7f, sizeof ( g ) );
    memset ( res, 0x7f, sizeof ( res ) );        
} 
bool read () {
    scanf ( "%d", &N );
    if ( N == -1 ) return false;   
    scanf ( "%s%s", s, e );
    beg = getId ( s );
    end = getId ( e );    
    for ( int i = 0; i < N; ++ i ) {
        scanf ( "%s%s%d", s, e, &v );
        int x = getId ( s ), y = getId ( e );
        g[x][y] = min ( g[x][y], v );
        g[y][x] = min ( g[y][x], v );    
    }
    return true;        
}
int DIS () {
    res[beg] = 0;
    priority_queue < Bus > q;
    q.push ( Bus ( beg, 0 ) );
    while ( !q.empty () ) {
        Bus t = q.top ();  q.pop ();
        if ( t.pos == end ) return t.val;
        for ( int i = 1; i < cnt; ++ i ) {
            if ( g[t.pos][i] != INF ) {
                if ( t.val + g[t.pos][i] < res[i] ) {
                    res[i] = t.val + g[t.pos][i];
                    q.push ( Bus ( i, res[i] ) );    
                }    
            }    
        }    
    }     
    return -1;
}
void prs () {
    printf ( "%d\n", DIS () );
}
int main()
{
    while ( init(), read () ) { 
        prs ();    
    }
    return 0;
}