#638171 (C++17) No.1460 Max of Min

• 問題: No.1460 Max of Min
• ユーザー: KoD
• 提出日時: 2021-04-01 12:01:59
• 言語: C++17 (gcc 13.3.0 + boost 1.89.0)
• 結果: AC
• 実行時間: 12 ms / 2,000 ms
• コード長: 3,652 bytes
• コンパイル時間: 3,955 ms
• コンパイル使用メモリ: 212,016 KB
• 最終ジャッジ日時: 2025-01-20 04:55:57
• ジャッジサーバーID （参考情報）: judge5 / judge1

ファイルパターン	結果
sample	AC * 3
other	AC * 91

ソースコード

#include <bits/stdc++.h>

using i32 = std::int32_t;
using u32 = std::uint32_t;
using i64 = std::int64_t;
using u64 = std::uint64_t;
using i128 = __int128_t;
using u128 = __uint128_t;
using isize = std::ptrdiff_t;
using usize = std::size_t;

class rep {
    struct Iter {
        usize itr;
        constexpr Iter(const usize pos) noexcept: itr(pos) { }
        constexpr void operator ++ () noexcept { ++itr; }
        constexpr bool operator != (const Iter& other) const noexcept { return itr != other.itr; }
        constexpr usize operator * () const noexcept { return itr; }
    };
    const Iter first, last;
public:
    explicit constexpr rep(const usize first, const usize last) noexcept: first(first), last(std::max(first, last)) { }
    constexpr Iter begin() const noexcept { return first; }
    constexpr Iter end() const noexcept { return last; }
};

template <class T, T Div = 2>
constexpr T INFTY = std::numeric_limits<T>::max() / Div;

template <class T>
bool setmax(T& lhs, const T& rhs) {
    if (lhs < rhs) {
        lhs = rhs;
        return true;
    }
    return false;
}

template <class T>
bool setmin(T& lhs, const T& rhs) {
    if (lhs > rhs) {
        lhs = rhs;
        return true;
    }
    return false;
}

template <class T>
using Vec = std::vector<T>;

template <class T>
using Heap = std::priority_queue<T, Vec<T>, std::greater<T>>;

void H_main() {
    usize K;
    u64 N;
    std::cin >> K >> N;
    Vec<i64> A(K), B(K);
    for (auto& x: A) {
        std::cin >> x;
    }
    for (auto& x: B) {
        std::cin >> x;
    }
    if (N < K) {
        std::cout << A[N] << '\n';
        return;
    }
    N -= K;
    A.resize(2 * K, -INFTY<i64>);
    for (auto i: rep(0, K)) {
        for (auto j: rep(0, K)) {
            setmax(A[i + K], std::min(A[i + j], B[j]));
        }
    }
    A.erase(A.begin(), A.begin() + K);
    const auto check = [&](const i64 threshold) {
        Vec<u64> T;
        T.reserve(K);
        for (auto i: rep(0, K)) {
            if (B[i] >= threshold) {
                T.push_back(K - i);
            }
        }
        if (T.empty()) {
            return false;
        }
        const auto min = T.back();
        Vec<u64> dist(min, INFTY<u64>);
        Vec<Vec<std::pair<usize, u64>>> graph(min);
        for (auto i: rep(0, min)) {
            for (const auto t: T) {
                graph[i].emplace_back((i + t) % min, t);
            }
        }
        Heap<std::pair<u64, usize>> que;
        const auto push = [&](const usize u, const u64 d) {
            if (setmin(dist[u], d)) {
                que.emplace(d, u);
            }
        };
        push(0, 0);
        while (!que.empty()) {
            const auto [d, u] = que.top();
            que.pop();
            if (dist[u] < d) {
                continue;
            }
            for (const auto [v, c]: graph[u]) {
                push(v, d + c);
            }
        }
        for (auto i: rep(0, K)) {
            if (i <= N && A[i] >= threshold) {
                const auto make = N - i;
                if (dist[make % min] <= make) {
                    return true;
                }
            }
        }
        return false;
    };
    Vec<i64> cand(2 * K);
    for (auto i: rep(0, K)) {
        cand[i] = A[i];
        cand[i + K] = B[i];
    }
    std::sort(cand.begin(), cand.end());
    usize ok = 0, ng = cand.size();
    while (ng - ok > 1) {
        const auto md = (ok + ng) / 2;
        (check(cand[md]) ? ok : ng) = md;
    }
    std::cout << cand[ok] << '\n';
    return;
}

int main() {
    std::ios_base::sync_with_stdio(false);
    std::cin.tie(nullptr);
    H_main(); 
    return 0;
}