#pragma GCC optimize ("O2") #pragma GCC target ("avx2") #include //#include //using namespace atcoder; using namespace std; typedef long long ll; #define rep(i, n) for(int i = 0; i < (n); i++) #define rep1(i, n) for(int i = 1; i <= (n); i++) #define co(x) cout << (x) << "\n" #define cosp(x) cout << (x) << " " #define ce(x) cerr << (x) << "\n" #define cesp(x) cerr << (x) << " " #define pb push_back #define mp make_pair #define chmin(x, y) x = min(x, y) #define chmax(x, y) x = max(x, y) #define Would #define you #define please const int SZ = 100001; class UF { public: int P[SZ + 1]; UF() : P() { rep1(i, SZ) P[i] = -1; } int find(int A) { if (P[A] < 0) return A; return P[A] = find(P[A]); } bool unite(int A, int B) { int a = find(A); int b = find(B); if (a == b) return false; if (P[a] > P[b]) swap(a, b); P[a] += P[b]; P[b] = a; return true; } } uf; int main() { cin.tie(0); ios::sync_with_stdio(false); int N, M; cin >> N >> M; int kotae = 1e9; tuple tp[100000]; rep(i, M) { int s, t, d; cin >> s >> t >> d; tp[i] = tie(d, s, t); } sort(tp, tp + M); reverse(tp, tp + M); #define PT pair vector E[200001]; rep(i, M) if (uf.find(1) != uf.find(N) || kotae == get<0>(tp[i])) { int d = get<0>(tp[i]); int s = get<1>(tp[i]); int t = get<2>(tp[i]); uf.unite(s, t); E[s].pb({ 1, t }); E[t].pb({ 1, s }); chmin(kotae, d); } ll D[100001]; rep1(i, N) D[i] = 1e18; priority_queue, greater> que; D[1] = 0; que.push(mp(0, 1)); while (que.size()) { PT p = que.top(); que.pop(); int i = p.second; if (D[i] != p.first) continue; for (PT p2 : E[i]) { int j = p2.second; ll d = D[i] + p2.first; if (D[j] > d) { D[j] = d; que.push(mp(d, j)); } } } cosp(kotae); co(D[N]); Would you please return 0; }