思路:
这题不难,就是有点恶心;
而且,请认真读题目(就是题目卡死劳资);
来,上代码:
#include <cmath>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm> using namespace std; #define maxn 807
#define maxm 860005
#define INF 0x7fffffff struct CityType {
double x[],y[],c;
};
struct CityType city[maxn]; int T,n,s,t,head[maxn],E[maxm],V[maxm];
int cnt,que[maxn<<]; double W[maxm],dis[maxn],c; bool if_[maxn]; inline double d(int now,int v1,int v2)
{
double x1=city[now].x[v1],x2=city[now].x[v2];
double y1=city[now].y[v1],y2=city[now].y[v2];
return (x1-x2)*(x1-x2)+(y1-y2)*(y1-y2);
} inline void edge_add(int u,int v,double w)
{
E[++cnt]=head[u],V[cnt]=v,W[cnt]=w,head[u]=cnt;
E[++cnt]=head[v],V[cnt]=u,W[cnt]=w,head[v]=cnt;
} double ds(int u,int v1,int v,int v2)
{
double xx=city[u].x[v1]-city[v].x[v2];
double yy=city[u].y[v1]-city[v].y[v2];
return sqrt(xx*xx+yy*yy);
} void spfa()
{
memset(if_,false,sizeof(if_));
memset(dis,0x7f,sizeof(dis));
int h=,tail=;que[]=s*-,que[]=s*-;
que[]=s*-,que[]=s*,if_[s*-]=true;
if_[s*-]=true,if_[s*-]=true,if_[s*]=true;
dis[s*-]=,dis[s*-]=,dis[s*-]=,dis[s*]=;
while(h<tail)
{
int now=que[h++];if_[now]=false;
for(int i=head[now];i;i=E[i])
{
if(dis[V[i]]>dis[now]+W[i])
{
dis[V[i]]=dis[now]+W[i];
if(!if_[V[i]]) if_[V[i]]=true,que[tail++]=V[i];
}
}
}
} int main()
{
scanf("%d",&T);
while(T--)
{
memset(head,,sizeof(head)),cnt=;
scanf("%d%lf%d%d",&n,&c,&s,&t);
for(int i=;i<=n;i++)
{
for(int v=;v<;v++) scanf("%lf%lf",&city[i].x[v],&city[i].y[v]);
scanf("%lf",&city[i].c);
double d01=d(i,,),d02=d(i,,),d12=d(i,,);
int pos=i*-;
if(d01+d02==d12)
{
city[i].x[]=city[i].x[]+city[i].x[]-city[i].x[];
city[i].y[]=city[i].y[]+city[i].y[]-city[i].y[];
}
else if(d01+d12==d02)
{
city[i].x[]=city[i].x[]+city[i].x[]-city[i].x[];
city[i].y[]=city[i].y[]+city[i].y[]-city[i].y[];
}
else
{
city[i].x[]=city[i].x[]+city[i].x[]-city[i].x[];
city[i].y[]=city[i].y[]+city[i].y[]-city[i].y[];
}
for(int j=;j<=;j++)
{
for(int v=j+;v<=;v++) edge_add(pos+j,pos+v,sqrt(d(i,j,v))*city[i].c);
}
}
for(int i=;i<=n;i++)
{
for(int j=i+;j<=n;j++)
{
int posi=i*-,posj=j*-;
for(int v=;v<;v++)
{
for(int z=;z<;z++) edge_add(v+posi,z+posj,ds(i,v,j,z)*c);
}
}
}
spfa();double ans=INF;
for(int i=;i<=;i++) ans=min(ans,dis[i+t*-]);
printf("%.1lf",ans);
}
return ;
}