一个小小二分+spfa
二分经过的最贵的点，然后跑spfa判断行不行。
没啥思维难度
#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#include<queue>
#define int long long
using namespace std;
int n,m;
int b;
int f[100001];
struct b{
int f,t,v;
int ne;
}ed[5000001];
int vis[100001];
int l,r;
queue <int> q;
int p;
int head[100001];
int dis[100001];
void add(int f,int t,int v){
p++;
ed[p].f=f;
ed[p].t=t;
ed[p].v=v;
ed[p].ne=head[f];
head[f]=p;
return ;
}
int x,y,z;
int check(int x){
memset(vis,0,sizeof(vis));
memset(dis,0x3f,sizeof(dis));
q.push(1);
vis[1]=1;
dis[1]=0;
while(!q.empty()){
int u=q.front();
q.pop();
vis[u]=0;
for(int i=head[u];i;i=ed[i].ne){
int v=ed[i].t;
if(f[v]>x)
continue;
if(dis[v]>dis[u]+ed[i].v){
dis[v]=dis[u]+ed[i].v;
if(!vis[v])
q.push(v);
}
}
}
return dis[n]<=b ? 1 : 0;
}
signed main(){
scanf("%lld%lld%lld",&n,&m,&b);
for(int i=1;i<=n;++i){
scanf("%lld",&f[i]);
}
for(int i=1;i<=m;++i){
scanf("%lld%lld%lld",&x,&y,&z);
add(x,y,z);
add(y,x,z);
}
int l=1;r=1000001001;
while(l<=r){
int mid=l+(r-l)/2;
if(check(mid))
r=mid-1;
else
l=mid+1;
}
if(l==1000001002)
cout<<"AFK";
else
cout<<l<<endl;
return 0;
}