AC code:
#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <algorithm>
using namespace std;
const int maxn=1005;
const int maxm=10010;

int n,P,K,L,Tmax;
int E[2*maxm],w[2*maxm],p[2*maxm],pre[2*maxm],fst[maxn],dist[maxn],vis[maxn],q[maxn+10];

void add(int a,int b,int c)
{
     E[++L]=b; w[L]=c; pre[L]=fst[a]; fst[a]=L;
}

void init()
{
     int a,b,c; L=Tmax=0;
     scanf("%d%d%d",&n,&P,&K);
     for(int i=1;i<=P;i++)
     {
         scanf("%d%d%d",&a,&b,&c);
         add(a,b,c); add(b,a,c); Tmax=max(Tmax,c);
     }
}

bool spfa(int v)
{
     for(int i=1;i<=L;i++) p[i]=w[i]<=v?0:1;
     int head,tail;
     memset(vis,0,sizeof(vis));
     memset(dist,127,sizeof(dist));
     head=1; tail=2; q[1]=1; dist[1]=0; vis[1]=1; 
     while(head!=tail)
     {
           int u=q[head];
           for(int k=fst[u];k;k=pre[k])
               if(dist[u]+p[k]<dist[E[k]])
               {
                  dist[E[k]]=dist[u]+p[k];
                  if(!vis[E[k]]) {vis[E[k]]=1; q[tail++]=E[k]; if(tail>n) tail-=n;}
               }
           vis[u]=0; head++; if(head>n) head-=n;
     }
     return(dist[n]<=K);
}

void work()
{
     int low=0,high=Tmax+1;
     while(low<high)
     {
           int mid=(low+high)/2;
           if(spfa(mid)) high=mid; else low=mid+1;
     }
     if((low+high)/2>Tmax) printf("-1\n"); else printf("%d\n",(low+high)/2);
}

int main()
{
    init();
    work();
    return 0;
}