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

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 1 #include<iostream>

 2 #include<map>

 3 #include<string>

 4 const int N=220;

 5 const int inf=1000000;

 6 using namespace std;

 7 

 8 int visited[N];

 9 int edge[N][N];

10 int dist[N];

11 map<string,int>mp;

12 

13 void Dijkstra(int v0,int v,int n){

14     memset(visited,0,sizeof(visited));

15     for(int i=1;i<=n;i++){

16         dist[i]=edge[v0][i];

17     }

18     dist[v0]=0;

19     visited[v0]=1;

20     for(int i=1;i<n;i++){

21         int min=inf,u=v0;

22         for(int j=1;j<=n;j++){

23             if(!visited[j]&&dist[j]<min){

24                 u=j,min=dist[j];

25             }

26         }

27         if(min==inf)break;

28         visited[u]=1;

29         for(int k=1;k<=n;k++){

30             if(!visited[k]&&dist[u]+edge[u][k]<dist[k]){

31                 dist[k]=dist[u]+edge[u][k];

32             }

33         }

34     }

35     if(dist[v]==inf){

36         printf("-1\n");

37     }else 

38         printf("%d\n",dist[v]);

39 }

40 

41 

42 int main(){

43     int n;

44     while(scanf("%d",&n)!=EOF){

45         if(n==-1)break;

46         mp.clear();

47         char s1[100],s2[100];

48         scanf("%s%s",s1,s2);

49         int count=0;

50         if(!mp[s1]){

51             mp[s1]=++count;

52         }

53         if(!mp[s2]){

54             mp[s2]=++count;

55         }

56         for(int i=1;i<=N;i++){

57             for(int j=1;j<=N;j++){

58                 if(i==j){

59                     edge[i][j]=0;

60                 }else

61                     edge[i][j]=inf;

62             }

63         }

64         char st[100],ed[100];

65         int len;

66         for(int i=1;i<=n;i++){

67             scanf("%s%s%d",st,ed,&len);

68             if(!mp[st]){

69                 mp[st]=++count;

70             }

71             if(!mp[ed]){

72                 mp[ed]=++count;

73             }

74             if(edge[mp[st]][mp[ed]]>len)

75                 edge[mp[st]][mp[ed]]=edge[mp[ed]][mp[st]]=len;

76         }

77         Dijkstra(mp[s1],mp[s2],mp.size());

78     }

79     return 0;

80 }