Idea: The path from A to B is, you can assume that the money at A is X, and when it reaches B, it is 100 (the meaning of the question), then you can find that 100=x*(z1% z2% …zb%) then x is exhausted If it is small, let (z1% z2% …zb%) be as large as possible, then we will find a path with the largest product.
//#pragma GCC optimize(2)#include<bits/stdc++.h>usingnamespace std;typedeflonglong ll;#define SIS std::ios::sync_with_stdio(false)#define space putchar(' ')#define enter putchar('\n')#define lson root<<1#define rson root<<1|1typedef pair<int,int> PII;constint mod=1e9+7;constint N=1e5+5;constint inf=0x7f7f7f7f;intgcd(int a,int b){
return b==0?a:gcd(b,a%b);}
ll lcm(ll a,ll b){
return a*(b/gcd(a,b));}template<classT>voidread(T &x){
char c;bool op =0;while(c =getchar(), c <'0'|| c >'9')if(c =='-')
op =1;
x = c -'0';while(c =getchar(), c >='0'&& c <='9')
x = x *10+ c -'0';if(op)
x =-x;}template<classT>voidwrite(T x){
if(x <0)
x =-x,putchar('-');if(x >=10)write(x /10);putchar('0'+ x %10);}
ll qsm(int a,int b,int p){
ll res=1%p;while(b){
if(b&1)
res=res*a%p;
a=1ll*a*a%p;
b>>=1;}return res;}double mp[2005][2005];double dis[N];int vis[N];int n,m,k;voiddj(int ts){
//memset(vis,0,sizeof vis);
dis[ts]=1;//vis[ts]=1;for(int i=1;i<=n;i++){
int t=-1;for(int j=1;j<=n;j++)if(!vis[j]&&(dis[t]<dis[j]||t==-1))
t=j;
vis[t]=1;for(int j=1;j<=n;j++)
dis[j]=max(dis[j],dis[t]*mp[t][j]);}}intmain(){
scanf("%d%d",&n,&m);for(int i=1;i<=m;i++){
int u,v,w;scanf("%d%d%d",&u,&v,&w);double z=(100.0-w)/100;
mp[v][u]=mp[u][v]=max(mp[u][v],z);}int ts,te;scanf("%d%d",&ts,&te);dj(ts);printf("%.8lf",100.0/dis[te]);return0;}