P1462 通往奥格瑞玛的道路

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#include<bits/stdc++.h>
using namespace std;typedef long long LL;
typedef pair<LL,int> PII;
const int N=1e4+10,M=1e5+10;int h[N],ne[M],idx,e[M],w[M];
int n,m;
LL b;
LL f[N];
LL dist[N];
bool st[N];void add(int a,int b,int c)
{e[idx]=b,ne[idx]=h[a],w[idx]=c,h[a]=idx++;
}bool dijkstra(LL limit)
{if(f[1]>limit||f[n]>limit) return false;memset(st,0,sizeof st);memset(dist,0x3f,sizeof dist);dist[1]=0;priority_queue<PII,vector<PII>,greater<PII>> heap;heap.push({dist[1],1});while(!heap.empty()){auto t=heap.top();heap.pop();int ver=t.second;if(st[ver]) continue;st[ver]=true;for(int i=h[ver];i!=-1;i=ne[i]){int j=e[i];if(f[j]>limit) continue;if(dist[j]>dist[ver]+w[i]){dist[j]=dist[ver]+w[i];heap.push({dist[j],j});}}}return dist[n]<=b;
}int main()
{memset(h,-1,sizeof h);ios::sync_with_stdio(0),cin.tie(0);cin>>n>>m>>b;for(int i=1;i<=n;i++) cin>>f[i];for(int i=1;i<=m;i++){int a,b,c;cin>>a>>b>>c;add(a,b,c),add(b,a,c);}LL max_fee=0;for(int i=1;i<=n;i++) max_fee=max(max_fee,f[i]);if(!dijkstra(max_fee+1)){cout<<"AFK"<<endl;return 0;}int l=0,r=max_fee;LL ans=b;while(l<=r){int mid=l+(r-l)/2;if(dijkstra(mid)){r=mid-1;ans=mid;}else{l=mid+1;}}cout<<ans<<endl;}