WA on #8 输出了AFK，应输出7...

#include<bits/stdc++.h>
using namespace std;
const int maxn=1e4+10;
const int inf=0x3f3f3f3f;
int n,m;
long long b;
int cost[maxn];
long long dis[maxn];
vector<pair<int,int> > e[maxn*5];
queue<int> q;
bool solve(int x){
    bool vis[maxn]={0};
    if(cost[1]>x) return false;
    for(int i=1;i<=n;i++) dis[i]=inf;
    dis[1]=0,vis[1]=1;q.push(1);
    while(!q.empty())
    {
        int u=q.front();q.pop();
        vis[u]=1;
        for(int i=0;i<(int)e[u].size();i++)
        {
            int v=e[u][i].first;
            if(dis[v]>dis[u]+e[u][i].second){
                if(!vis[v]&&cost[v]<=x){
                    dis[v]=dis[u]+e[u][i].second;
                    q.push(v),vis[v]=1;
                }
            }
        }
    }
    if(dis[n]<=b) return true;
    else return false;
}
int main(){
    // freopen("P1462_8.in","r",stdin);
    cin>>n>>m>>b;
    int l=0,r=0;
    for(int i=1;i<=n;i++) cin>>cost[i],r=max(r,cost[i]);
    for(int i=1;i<=m;i++)
    {
        int u,v,w;
        cin>>u>>v>>w;
        e[u].push_back(make_pair(v,w));
        e[v].push_back(make_pair(u,w));
    }
    if(!solve(inf)){cout<<"AFK";return 0;}
    while(l<=r)//二分枚举交费最多的一次
    {
        int mid=(l+r)/2;
        // cout<<l<<" "<<r<<" "<<mid<<" "<<spfa(mid)<<endl;
        if(solve(mid)) r=mid-1;
        else l=mid+1;
    }
    cout<<l;
}

感谢大佬