P1462 二分

#include <bits/stdc++.h>
#define INF 0x3f3f3f3f
#define SI(a) scanf("%d",&a)
#define ms(a,x) memset(a,x,sizeof(a))
typedef long long ll;
const int mod = 998244353;
const int maxn = 1e6+10;
using namespace std;
int ans;
int a[maxn];
struct Edge{
    
    
    int from,to,dis;
};
struct HeapNode{
    
    
    int d,u;
    bool operator < (const HeapNode& rhs) const{
    
    
        return d > rhs.d;
    }
};
int n,m,b;//点数，边数,起始
int cnt;
vector<Edge>edges;
vector<int>G[maxn];//每个节点出发的边编号
bool done[maxn];
int dis[maxn];//距离
int p[maxn];//最短路的上一条边

void init(int n){
    
    
    for(int i = 0;i <= n;i++)G[i].clear();
    cnt = 0;
    edges.clear();
}
void AddEdge(int from,int to,int dis){
    
    
    edges.push_back((Edge){
    
    from,to,dis});
    //edges.push_back((Edge){to,from,dis});//无向图/边
    cnt = edges.size();
    G[from].push_back(cnt-1);

}
bool Dijkstra(int val){
    
    
    priority_queue<HeapNode>Q;
    for(int i = 0;i <= n;i++)dis[i] = INF;
    dis[1] = 0;
    //for(int i = 0;i < n;i++)cout<<dis[i]<<endl;
    ms(done,false);
    Q.push((HeapNode){
    
    0,1});
    while(!Q.empty())
    {
    
    
        HeapNode x = Q.top();Q.pop();
        int u = x.u;
        if(done[u])continue;
        done[u] = true;
        //cout<<"1 "<<G[u].size()<<endl;
        for(int i = 0;i <(int)G[u].size();i++)
        {
    
    
            Edge& e = edges[G[u][i]];
            //cout<<e.dis<<endl;
            if(dis[e.to] > dis[u] + e.dis && a[e.to] <= val){
    
    
                dis[e.to] = dis[u]+ e.dis;
                //p[e.to] = G[u][i];
                Q.push((HeapNode){
    
    dis[e.to],e.to});
            }
        }
    }
    /*for(int i = 1;i <= n;i++)
    cout<<dis[i]<<endl;*/
    return dis[n] <= b;
}
int main()
{
    
    
    int l,r = -1;
    cin>>n>>m>>b;
    //cout<<n<<" "<<m<<" "<<b<<endl;
    init(n);
    for(int i = 1;i <= n;i++){
    
    
        scanf("%d",&a[i]);
        if(r < a[i])
            r = a[i];
    }
    /*for(int i = 1;i <= n;i++)
        cout<<a[i]<<endl;*/
    l = min(a[1],a[n]);
    //cout<<l<<" "<<r<<endl;
    //cout<<"haha"<<endl;
    for(int i = 0;i < m;i++)
    {
    
    
        int u,v,dis;
        cin>>u>>v>>dis;
        AddEdge(u,v,dis);
        AddEdge(v,u,dis);
    }
    if(!Dijkstra(r))cout<<"AFK"<<endl;
    else{
    
    
    while(l != r)
    {
    
    
        int mid = l + (r-l)/2;
        //cout<<mid<<endl;
        if(!Dijkstra(mid))l = mid+1;
        else r = mid ;
    }
    cout<<l<<endl;
    }
    return 0;
}