URAL 1934 Black Spot --- 最短的简单修改

#include <iostream>
#include <cstdlib>
#include <cstring>
#include <string>
#include <cstdio>
#include <cmath>
#include <algorithm>
#include <vector>
#include <queue>
#include <map>
#define inf 0x3f3f3f3f
#define eps 1e-6
#define ll long long
const int maxn=100010;
const int maxm=100010;
using namespace std;

struct node
{
int v,w,next;
double p;
}e[maxm<<1];
int vis[maxn],h,head[maxn],n,m,d[maxn],pre[maxn];
double p[maxn];

void addedge(int a,int b,double c)
{
e[h].v=b;
e[h].w=1;
e[h].p=c;
e[h].next=head[a];
head[a]=h++;
}

void spfa(int s)
{
int x,v,i;
for(i=0;i<=n;i++)
p[i]=0,d[i]=inf;
memset(vis,0,sizeof vis);
memset(pre,-1,sizeof pre);
p[s]=1,vis[s]=1,d[s]=0;
queue<int> q;
q.push(s);
while(!q.empty())
{
x=q.front();
q.pop();
vis[x]=0;
for(i=head[x];i!=-1;i=e[i].next)
{
v=e[i].v;
if(d[v]>d[x]+1)
{
d[v]=d[x]+1;
p[v]=p[x]*e[i].p;
pre[v]=x;
if(!vis[v])
{
vis[v]=1;
q.push(v);
}
}
else if(d[v]==d[x]+1)
{
if(p[v]<p[x]*e[i].p)
{
p[v]=p[x]*e[i].p;
pre[v]=x;
if(!vis[v])
{
vis[v]=1;
q.push(v);
}
}
}
}
}
return ;
}
int flag;
void output(int x)
{
if(pre[x]!=-1)
output(pre[x]);
if(flag) flag=0;
else putchar(' ');
printf("%d",x);
}

int main()
{
int a,b,s,t;
double c;
while(~scanf("%d%d",&n,&m))
{
h=0;
memset(head,-1,sizeof head);
scanf("%d%d",&s,&t);
while(m--)
{
scanf("%d%d%lf",&a,&b,&c);
addedge(a,b,1-c/100);
addedge(b,a,1-c/100);
}
spfa(s);
printf("%d %.8lf\n",d[t]+1,1-p[t]);
flag=1;
output(t);
puts("");
}
return 0;
}