萌新 spfa AC#4#7#11，其它RE，求助

RT

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int maxn=10001+10;
const int maxm=50001+10;
const int INF=0x3f3f3f3f;
int n,m,b,cnt=0,ans=-1;
ll f[maxn],dis[maxn];
int head[maxn];
bool vis[maxn];
struct edge
{
  int next,to,val;
}bian[maxm];
void ins(int u,int v,int c)
{
  bian[++cnt].to=v;
  bian[cnt].val=c;
  bian[cnt].next=head[u];
  head[u]=cnt;
}
bool spfa(int k)
{
  queue <int> q;
  if(f[1]>k)  return false;
  dis[1]=0;vis[1]=true;
  q.push(1);
  while(!q.empty())
  {
    int u=q.front();
    q.pop();
    vis[u]=false;
    for(int e=head[u];e;e=bian[e].next)
      if(dis[bian[e].to]>dis[u]+bian[e].val && f[bian[e].to]<=k)
      {
        dis[bian[e].to]=dis[u]+bian[e].val;
        if(!vis[bian[e].to])  {vis[bian[e].to]=true;q.push(bian[e].to);}
      }
  }
  if(dis[n]>b)  return false;
  return true;
}

int main()
{
    scanf("%d%d%d",&n,&m,&b);
    for(int i=1;i<=n;i++)
      scanf("%lld",&f[i]);
    for(int i=1;i<=m;i++)
    {
      int u,v,c;
      scanf("%d%d%d",&u,&v,&c);
      ins(u,v,c);
      ins(v,u,c);
    }
    int l=0,r=1000000001;
    while(l<=r)
    {
      int mid=(l+r)>>1;
      memset(vis,false,sizeof(vis));
      memset(dis,INF,sizeof(dis));
      if(spfa(mid))  {ans=mid;r=mid-1;}
      else  l=mid+1;
    }
    if(ans==-1)  printf("AFK");
    else  printf("%d",ans);
    return 0;
}