dij+二分求助

存图用的邻接点列表，不是前向星

#include<bits/stdc++.h>
#define INF 0x3f3f3f3f
using namespace std;
const int MAXN=10008;
typedef pair<int,int> pi;
priority_queue< pi,vector<pi>,greater<pi> > q;
int n,m,b;
int f[MAXN],dis[MAXN];
struct node{
    int v,w;
};
vector<node> a[MAXN];
bool vis[MAXN];
int l=INT_MAX,r=INT_MIN,mid;
bool dijkstra(int st){
    memset(vis,0,sizeof(vis));
    memset(dis,INF,sizeof(dis));
    dis[1]=st;
    q.push({make_pair(dis[1],1)});
    while(!q.empty()){
        int x=q.top().second;
        q.pop();
        if(vis[x]) continue;
        vis[x]=true;
        for(int i=0;i<a[x].size();i++){
            int y=a[x][i].v,z=a[x][i].w;
            dis[y]=min(dis[y],dis[x]+z);
            q.push(make_pair(dis[y],y));
        }
    }
    return dis[n]<b;
}
int main(){
    scanf("%d%d%d",&n,&m,&b);
    for(int i=1;i<=n;i++){
        scanf("%d",&f[i]);
        l=min(l,f[i]);
        r=max(r,f[i]);
    }
    int maxi=r;
    for(int i=1;i<=n;i++){
        int u,v,w;
        scanf("%d%d%d",&u,&v,&w);
        a[u].push_back({v,w});
        a[v].push_back({u,w});
    }
    while(l<=r){
        mid=(l+r)/2;
        if(dijkstra(mid)) r=mid-1;
        else l=mid+1;
    }
    if(l==maxi+1) 
        printf("AFK\n");
    else
        printf("%d\n",l);
    return 0;
}