poj 2263 Heavy Cargo(floyd)

floyd

#include<stdio.h>#include<string.h>#include<algorithm>#include<string>#include<map>#include<iostream>using namespace std;int n,m,edge[250][250],vis[250],dist[250];map<string,int>a;void floyd(){    int i,j,k,t;    for(k=1; k<=n; k++)        for(i=1; i<=n; i++)            for(j=1; j<=n; j++)            {                if(edge[i][k]==-1||edge[k][j]==-1) continue;                t=min(edge[i][k],edge[k][j]);                if(edge[i][j]==-1) edge[i][j]=t;                else if(edge[i][j]<t) edge[i][j]=t;            }}int main(){    int i,j,tot,st,ed,cas=0,u,v,w;    string s1,s2;    while(~scanf("%d%d",&n,&m))    {        memset(edge,0,sizeof(edge));        if(n==0&&m==0) break;        a.clear();        tot=1;        for(i=0; i<m; i++)        {            cin>>s1>>s2>>w;            if(a[s1]==0)            {                a[s1]=tot;                tot++;            }            if(a[s2]==0)            {                a[s2]=tot;                tot++;            }            u=a[s1];            v=a[s2];            edge[u][v]=w;            edge[v][u]=w;        }        for(i=1; i<=n; i++)            for(j=1; j<=n; j++)            {                if(edge[i][j]==0) edge[i][j]=-1;            }        cin>>s1>>s2;        st=a[s1];        ed=a[s2];        floyd();        printf("Scenario #%d\n",++cas);        printf("%d tons\n\n",edge[st][ed]);    }    return 0;}