Uva-10816-Travel in Desert

#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#include<queue>
using namespace std;
const double eps=1e-8;
const int inf=1<<29;
const int maxn=1010;
const int maxm=2e5+100;
int e,n,m,st,des,head[maxn],nxt[maxm],pnt[maxm],pre[maxn],costr[maxm],costd[maxm],dist[maxn];
bool vis[maxn];
queue<int> q;
void AddEdge(int u,int v,int cr,int cd)
{
pnt[e]=v;nxt[e]=head[u];costr[e]=cr;costd[e]=cd;head[u]=e++;
pnt[e]=u;nxt[e]=head[v];costr[e]=cr;costd[e]=cd;head[v]=e++;
}
void DFS(int u)
{
if(u==st)
{
printf("%d",st);
return;
}
DFS(pre[u]);
printf(" %d",u);
}
bool Spfa(int st,int des,int val)
{
memset(pre,-1,sizeof(pre));
for(int i=0;i<=n;i++)
dist[i]=inf;
dist[st]=0;
q.push(st);
while(!q.empty())
{
int u=q.front();
vis[u]=0;
q.pop();
for(int i=head[u];i!=-1;i=nxt[i])
{
if(costr[i]<=val&&dist[pnt[i]]>dist[u]+costd[i])
{
dist[pnt[i]]=dist[u]+costd[i];
pre[pnt[i]]=u;
if(!vis[pnt[i]])
{
q.push(pnt[i]);
vis[pnt[i]]=1;
}
}
}
}
if(dist[des]!=inf)
return true;
return false;
}
int main()
{
while(scanf("%d%d",&n,&m)!=EOF)
{
e=0;
memset(head,-1,sizeof(head));
scanf("%d%d",&st,&des);
int sl=inf,sr=0;
for(int i=0;i<m;i++)
{
int u,v,r,d;
int sa1,sa2,sb1,sb2;
scanf("%d%d%d.%d%d.%d",&u,&v,&sa1,&sa2,&sb1,&sb2);
r=sa1*10+sa2;
d=sb1*10+sb2;
AddEdge(u,v,r,d);
sl=min(sl,r);
sr=max(sr,r);
}
int ans=0;
while(sl<=sr)
{
int mid=(sl+sr)>>1;
if(Spfa(st,des,mid))
{
ans=mid;
sr=mid-1;
}
else
sl=mid+1;
}
Spfa(st,des,ans);
DFS(des);
printf("\n");
printf("%.1f %.1f\n",dist[des]*1.0/10,ans*1.0/10);
}
return 0;
}