提出 #49157358

---

ソースコード 拡げる

#include <bits/stdc++.h>
#include <atcoder/modint>
#include <atcoder/dsu>

namespace {
    using ModInt [[maybe_unused]] = atcoder::modint998244353;
    using Num [[maybe_unused]] = long long int;
    using Vec [[maybe_unused]] = std::vector<Num>;
    using Set [[maybe_unused]] = std::set<Num>;
    using Mset [[maybe_unused]] = std::multiset<Num>;
    using Edges [[maybe_unused]] = std::vector<std::vector<Num>>;

    template<typename T>
    using Q [[maybe_unused]] = std::queue<T>;

    template<typename T>
    using PQ [[maybe_unused]] = std::priority_queue<T, std::vector<T>, std::greater<T>>;
}

void solve(std::istream& is, std::ostream& os) {
    Num n, m;
    is >> n >> m;

    Vec aset(n);
    for(auto&& a : aset) {
        is >> a;
    }

    atcoder::dsu tree(n);

    std::vector<std::pair<Num, Num>> es;
    for(Num i{0}; i<m; ++i) {
        Num u, v;
        is >> u >> v;
        --u;
        --v;

        if (aset.at(u) == aset.at(v)) {
            tree.merge(u, v);
        } else if (aset.at(u) < aset.at(v)) {
            es.push_back(std::make_pair(u, v));
        } else {
            es.push_back(std::make_pair(v, u));
        }
    }

    Edges edges(n);
    for(const auto& [u, v] : es) {
        edges[tree.leader(u)].push_back(tree.leader(v));
    }

    Vec distances(n, -1000000000LL);
    PQ<std::tuple<Num, Num, Num>> q;
    const auto start = tree.leader(0);
    distances.at(start) = 1;
    q.push(std::make_tuple(aset.at(start), -1, start));

    while(!q.empty()) {
        const auto [a_from, dist, raw_from] = q.top();
        const auto from = tree.leader(raw_from);
        q.pop();

        const auto next_dist = 1 - dist;
        for(const auto& raw_to : edges[from]) {
            const auto to = tree.leader(raw_to);
            const auto a_to = aset.at(to);

            if (distances.at(to) < next_dist) {
                distances.at(to) = next_dist;
                q.push(std::make_tuple(a_to, -next_dist, to));
            }
        }
    }

    const Num goal = tree.leader(n-1);
    const Num answer = std::max(0LL, distances.at(goal));
    os << answer << "\n";
}

int main(void) {
    solve(std::cin, std::cout);
    return 0;
}

提出情報

ジャッジ結果