1072. Gas Station (30) PAT 甲级

#include<stdio.h>
#include<string.h>
#include<vector>
#include<algorithm>

using namespace std;

#define MAX_V 1100
#define INF 1000000000

int G[MAX_V][MAX_V];
int n,m,k,ds;
int d[MAX_V];
bool visited[MAX_V];

void Dijkstra(int s){
memset(visited,false,sizeof(visited));
fill(d,d+MAX_V,INF);

d[s]=0;
for(int i=0;i<n+m;i++){
int u=-1,Min=INF;
for(int j=1;j<=n+m;j++){
if(!visited[j]&&d[j]<Min){
u=j;
Min=d[j];
}
}
if(u==-1)   return;
visited[u]=true;
for(int v=1;v<=n+m;v++){
if(!visited[v]&&G[u][v]!=INF){
if(d[u]+G[u][v]<d[v]){
d[v]=d[u]+G[u][v];
}
}
}
}
}

int getID(char str[]){
int len=strlen(str);
int id=0;
for(int i=0;i<len;i++){
if(str[i]!='G'){
id=id*10+str[i]-'0';
}
}
if(str[0]=='G') return n+id;
return id;
}

int main(){
scanf("%d%d%d%d",&n,&m,&k,&ds);
char house1[5],house2[5];
int dis,u,w;
fill(G[0],G[0]+MAX_V*MAX_V,INF);
for(int i=0;i<k;i++){
scanf("%s %s %d",house1,house2,&dis);
int u=getID(house1);
int v=getID(house2);
G[u][v]=G[v][u]=dis;
}
double ansDis=-1;
double ansAvg=INF;

int ansID=-1;

for(int i=n+1;i<=n+m;i++){
double min=INF,avg=0;
Dijkstra(i);
for(int j=1;j<=n;j++){
if(d[j]>ds){
min=-1;
break;
}
if(d[j]<min)    min=d[j];
avg+=1.0*d[j]/n;
}
if(min==-1) continue;
if(min>ansDis){
ansDis=min;
ansID=i;
ansAvg=avg;
}
else{
if(min==ansDis&&avg<ansAvg){
ansID=i;
ansAvg=avg;
}
}
}

if(ansID==-1)   printf("No Solution\n");
else{
printf("G%d\n",ansID-n);
printf("%.1f %.1f",ansDis,ansAvg);
}
}