Submission #68256456

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
#if __has_include(<atcoder/all>)
#include <atcoder/all>
using namespace atcoder;
#endif
#ifndef ONLINE_JUDGE
#define _GLIBCXX_DEBUG
#include <iostream>
template <typename T, typename U>
ostream& operator<<(ostream& os, const pair<T, U>& p) {return os<<'(' <<p.first<<", "<<p.second<<')';}
template <typename T>
ostream& operator<<(ostream& os, const vector<T>& v) {os<<'[';for(auto it=v.begin();it!=v.end();++it){os<<*it; if(next(it)!=v.end()){os<<", ";}}return os<<']';}
template <typename T>
ostream& operator<<(ostream& os, const vector<vector<T>>& vv) {os<<"[\n";for(auto it=vv.begin();it!=vv.end();++it){os<<"  "<<*it;if(next(it)!=vv.end()){os<<",\n";}else{os<<"\n";}}return os<<"]";}
#define dump(x) cerr << #x << " = " << (x) << '\n'
#else
#define dump(x) (void)0
#endif
using ll = long long;
using ld = long double;
using P = pair<ll,ll>;
template<class T> using pq = priority_queue<T>;
template<class T> using pq_g = priority_queue<T, vector<T>, greater<T>>;
#define out(x) cout<<x<<'\n'
#define all(v) (v).begin(),(v).end()
#define rall(v) (v).rbegin(),(v).rend()
#define OVERLOAD_REP(_1,_2,_3,name,...) name
#define REP1(i,n) for (auto i = std::decay_t<decltype(n)>{}; (i) != (n); ++(i))
#define REP2(i, l, r) for (auto i = (l); (i) != (r); ++(i))
#define rep(...) OVERLOAD_REP(__VA_ARGS__, REP2, REP1)(__VA_ARGS__)
template<class T> inline bool chmin(T& a, T b) {if(a > b){a = b; return true;} else {return false;}};
template<class T> inline bool chmax(T& a, T b) {if(a < b){a = b; return true;} else {return false;}};
const ll INF=(1LL<<60);
const ll mod=998244353;
using Graph = vector<vector<ll>>;
using Network = vector<vector<pair<ll,ll>>>;
using Grid = vector<string>;
const int dx[4] = {1, 0, -1, 0};
const int dy[4] = {0, 1, 0, -1};
const int dx2[8] = {1, 1,  1, 0,  0, -1, -1, -1};
const int dy2[8] = {1, 0, -1, 1, -1,  1,  0, -1};

void solve() {
    ll N, M;
    cin >> N >> M;
    Network G(N);
    rep(i, M) {
        ll u, v, w;
        cin >> u >> v >> w;
        --u; --v;
        G[u].emplace_back(v, w);
        G[v].emplace_back(u, w);
    }
    ll ans = (1LL << 31) - 1;
    for (int b = 30; b >= 0; --b) {
        ll mask = (1LL << b);
        bitset<200001> seen(0);
        seen[0] = 1;
        queue<ll> q;
        q.push(0);
        while (!q.empty()) {
            ll v = q.front();
            q.pop();
            bool reached = false;
            for (auto& [u, w] : G[v]) {
                if ((ans | w) == ans && (w & mask) == 0 && !seen[u]) {
                    seen[u] = 1;
                    q.push(u);
                    if (u == N - 1) {
                        reached = true;
                        break;
                    }
                }
            }
            if (reached) break;
        }
        if (seen[N - 1]) {
            ans ^= mask;
        }
    }
    out(ans);
}

int main() {
    cin.tie(0);
    ios_base::sync_with_stdio(false);
    int t = 1;
    while (t--) {
        solve();
    }
    return 0;
}

Submission Info

Judge Result