Ohoo

#include <fstream>
#include <vector>
#include <bitset>
using namespace std;
ifstream fin("Ohoo.in");
ofstream fout("Ohoo.out");
#define Nmax 100005
vector<pair<int,int> > v[Nmax];
bitset<Nmax> vis;
bool t;
int n, m;

void dfs(int node, int d)
{
    if(node==n) t=1;
    else
    {
    vis[node] = 1;
    for (auto i : v[node])
        if (!t &&  i.second<=d  && !vis[i.first])
        {dfs(i.first,d); }
    }
}

int main()
{
    fin >> n >> m;
    int mz = 0;

    for (int i = 1, x, y, c; i <= m; ++i)
    {
        fin >> x >> y>> c;
        v[x].push_back(make_pair(y,c));
        v[y].push_back(make_pair(x,c));
        if(c>mz) mz=c;
    }

    int st=1,dr=mz,sol=mz;
    while(st<=dr)
    {
        int mij=(st+dr)/2;
        for (int i=1;i<=n;++i) vis[i]=0;
        dfs(1,mij);
        if(t) {sol=mij; t=0; dr=mij-1;}
        else st=mij+1;
    }
    fout<<sol<<'\n';
    return 0;
}