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#include <bits/stdc++.h>
using namespace std;
#define rep(i, a, n) for (int i = a; i < n; ++i)
#define per(i, a, n) for (int i = n - 1; i >= a; --i)
#define fi first
#define se second
#define pb push_back
#define np next_permutation
#define INF 0x3f3f3f3f
#define EPS 1e-8
#define eps '\n'
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef pair<string, string> pss;
typedef vector<int> vi;
const int maxn = 1e5 + 5;
struct edge {
int u, v, w;
edge(int _u, int _v, int _w)
: u(_u)
, v(_v)
, w(_w)
{
}
edge() {}
};
vector<edge> e[maxn];
int vis[maxn];
int n, m, ans, ss, tt;
inline void addEdge(int u, int v, int w)
{
e[u].push_back(edge(u, v, w));
}
bool check(int mid)
{
queue<int> q;
memset(vis, 0, sizeof(int) * (n + 1));
q.push(ss);
vis[ss] = 1;
int now, nxt;
while (!q.empty()) {
now = q.front();
q.pop();
rep(i, 0, e[now].size())
{
int tempv = e[now][i].v;
int tempw = e[now][i].w;
if (vis[tempv] || tempw > mid)
continue;
else {
vis[tempv] = 1;
if (tempv == tt)
return true;
q.push(tempv);
}
}
}
return false;
}
int main()
{
ios::sync_with_stdio(false);
while (cin >> n >> m >> ss >> tt) {
ans = 1e4 + 5;
int tu, tv, tw;
rep(i, 0, n + 1) e[i].clear();
rep(i, 1, m + 1)
{
cin >> tu >> tv >> tw;
addEdge(tu, tv, tw);
addEdge(tv, tu, tw);
}
int l = 0;
int r = 1e4 + 5;
int mid;
while (l < r) {
mid = (l + r) >> 1;
if (check(mid))
r = mid;
else
l = mid + 1;
}
cout << l << endl;
}
}
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