hdu 2112 map+Dijkstra

很好的一道题。。。一次水过。。。不过效率不是很高。。都2000MS+了。。。orz

#include<iostream>
#include<map>
#include<string>
const int N=220;
const int inf=1000000;
using namespace std;

int visited[N];
int edge[N][N];
int dist[N];
map<string,int>mp;

void Dijkstra(int v0,int v,int n){
    memset(visited,0,sizeof(visited));
    for(int i=1;i<=n;i++){
        dist[i]=edge[v0][i];
    }
    dist[v0]=0;
    visited[v0]=1;
    for(int i=1;i<n;i++){
        int min=inf,u=v0;
        for(int j=1;j<=n;j++){
            if(!visited[j]&&dist[j]<min){
                u=j,min=dist[j];
            }
        }
        if(min==inf)break;
        visited[u]=1;
        for(int k=1;k<=n;k++){
            if(!visited[k]&&dist[u]+edge[u][k]<dist[k]){
                dist[k]=dist[u]+edge[u][k];
            }
        }
    }
    if(dist[v]==inf){
        printf("-1\n");
    }else 
        printf("%d\n",dist[v]);
}


int main(){
    int n;
    while(scanf("%d",&n)!=EOF){
        if(n==-1)break;
        mp.clear();
        char s1[100],s2[100];
        scanf("%s%s",s1,s2);
        int count=0;
        if(!mp[s1]){
            mp[s1]=++count;
        }
        if(!mp[s2]){
            mp[s2]=++count;
        }
        for(int i=1;i<=N;i++){
            for(int j=1;j<=N;j++){
                if(i==j){
                    edge[i][j]=0;
                }else
                    edge[i][j]=inf;
            }
        }
        char st[100],ed[100];
        int len;
        for(int i=1;i<=n;i++){
            scanf("%s%s%d",st,ed,&len);
            if(!mp[st]){
                mp[st]=++count;
            }
            if(!mp[ed]){
                mp[ed]=++count;
            }
            if(edge[mp[st]][mp[ed]]>len)
                edge[mp[st]][mp[ed]]=edge[mp[ed]][mp[st]]=len;
        }
        Dijkstra(mp[s1],mp[s2],mp.size());
    }
    return 0;
}