55 lines
1.1 KiB
C++
55 lines
1.1 KiB
C++
#include<cstdio>
|
|
#include<cstring>
|
|
#include<algorithm>
|
|
#include<vector>
|
|
#include<deque>
|
|
using namespace std;
|
|
const int maxn=1005;
|
|
const int maxm=10005;
|
|
int n,m,Q,dis[maxn],vis[maxn];
|
|
struct Edge { int v,w; Edge *nxt; };
|
|
Edge mem[maxm*2],*G[maxn],*ecnt=mem;
|
|
inline void AddEdge(int u,int v,int w) { ecnt->v=v; ecnt->w=w; ecnt->nxt=G[u]; G[u]=ecnt++; }
|
|
int cal(int cost)
|
|
{
|
|
memset(dis,0x3f,sizeof(dis)); memset(vis,0,sizeof(vis));
|
|
dis[1]=0;
|
|
deque<int> Q; Q.push_back(1);
|
|
while(Q.size())
|
|
{
|
|
int u=Q.front(); Q.pop_front();
|
|
if(vis[u]) continue;
|
|
vis[u]=1;
|
|
for(Edge *it=G[u];it;it=it->nxt)
|
|
{
|
|
int v=it->v,w=(it->w>cost?1:0);
|
|
dis[v]=min(dis[v],dis[u]+w);
|
|
if(w) Q.push_back(v);
|
|
else Q.push_front(v);
|
|
}
|
|
}
|
|
return dis[n];
|
|
}
|
|
int main()
|
|
{
|
|
#ifdef local
|
|
freopen("pro.in","r",stdin);
|
|
#endif
|
|
scanf("%d%d%d",&n,&m,&Q);
|
|
int L=0,R=0,M,res;
|
|
for(int i=0;i<m;i++)
|
|
{
|
|
int u,v,w; scanf("%d%d%d",&u,&v,&w);
|
|
AddEdge(u,v,w); AddEdge(v,u,w);
|
|
R=max(R,w);
|
|
}
|
|
res=R+1; int oo=R+1;
|
|
while(L<=R)
|
|
{
|
|
M=(L+R)>>1;
|
|
if(cal(M)<=Q) res=M,R=M-1;
|
|
else L=M+1;
|
|
}
|
|
printf("%d\n",res==oo?-1:res);
|
|
return 0;
|
|
} |