#868691 (C++17) No.2301 Namorientation

• 問題: No.2301 Namorientation
• ユーザー: sten_san
• 提出日時: 2023-05-12 21:57:31
• 言語: C++17 (gcc 15.2.0 + boost 1.90.0)
• 結果: CE
  (最新)
  AC
  (最初)
• 実行時間: -
• コード長: 3,531 bytes
• コンパイル時間: 1,210 ms
• コンパイル使用メモリ: 211,232 KB
• 最終ジャッジ日時: 2026-06-30 14:51:01
• 合計ジャッジ時間: 2,090 ms
• ジャッジサーバーID （参考情報）: judge1_0 / judge2_0

コンパイルメッセージ

main.cpp: In instantiation of 'constexpr auto fix(F&&) [with F = main()::<lambda(auto:33, int, int)>&]':
main.cpp:73:34:   required from 'constexpr auto fix(F&&) [with F = main()::<lambda(auto:33, int, int)>]'
   73 |         return std::get<0>(f)(fix(std::get<0>(f)), std::forward<decltype(args)>(args)...);
      |                               ~~~^~~~~~~~~~~~~~~~
main.cpp:107:8:   required from here
  107 |     fix([&](auto f, int v, int p = -1) -> void {
      |     ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  108 |         if (p != -1) {
      |         ~~~~~~~~~~~~~~
  109 |             d[{ v, p }] = true;
      |             ~~~~~~~~~~~~~~~~~~~
  110 |         }
      |         ~
  111 | 
      |         
  112 |         for (auto u : h[v]) {
      |         ~~~~~~~~~~~~~~~~~~~~~
  113 |             if (u == p) {
      |             ~~~~~~~~~~~~~
  114 |                 continue;
      |                 ~~~~~~~~~
  115 |             }
      |             ~
  116 |             f(u, v);
      |             ~~~~~~~~
  117 |         }
      |         ~
  118 |     })(sa);
      |     ~~  
main.cpp:73:34: error: use of 'constexpr auto fix(F&&) [with F = main()::<lambda(auto:33, int, int)>&]' before deduction of 'auto'
   73 |         return std::get<0>(f)(fix(std::get<0>(f)), std::forward<decltype(args)>(args)...);
      |                               ~~~^~~~~~~~~~~~~~~~
main.cpp:73:34: error: use of 'constexpr auto fix(F&&) [with F = main()::<lambda(auto:33, int, int)>&]' before deduction of 'auto'

ソースコード

#include <bits/stdc++.h>
using namespace std;

struct iofast_t {
    iofast_t() {
        ios::sync_with_stdio(false);
        cin.tie(nullptr);
    }
} iofast;

struct uns_t {} uns;
template <typename Element, typename Head, typename ...Args>
auto vec(Element init, Head arg, Args ...args) {
    if constexpr (sizeof...(Args) == 0) return vector(arg, init);
    else return vector(arg, vec(init, args...));
}
template <typename Element, typename Head, typename ...Args>
auto vec(uns_t, Head arg, Args ...args) {
    return vec(Element(), arg, args...);
}

template <typename Container>
auto distance(const Container &c, decltype(begin(c)) iter) {
    return distance(begin(c), iter);
}

template <typename RIter, typename Compare = less<typename iterator_traits<RIter>::value_type>>
auto isort(RIter first, RIter last, Compare comp = Compare()) {
    vector<int> i(distance(first, last));
    iota(begin(i), end(i), 0);
    sort(begin(i), end(i), [&](auto x, auto y) {
        return comp(*(first + x), *(first + y));
    });
    return i;
}

template <typename, template <typename> typename, typename = void_t<>>
struct detect : false_type {};
template <typename T, template <typename> typename Check>
struct detect<T, Check, void_t<Check<T>>> : true_type {};
template <typename T, template <typename> typename Check>
constexpr inline bool detect_v = detect<T, Check>::value;

template <typename T>
using has_member_sort = decltype(declval<T>().sort());

template <typename Container, typename Compare = less<typename Container::value_type>>
auto sorted(Container c, Compare comp = Compare()) {
    if constexpr (detect_v<Container, has_member_sort>) {
        c.sort(comp);
        return c;
    }
    else {
        sort(begin(c), end(c), comp);
        return c;
    }
}

template <typename Container, typename Compare = equal_to<typename Container::value_type>>
auto uniqued(Container c, Compare comp = Compare()) {
    c.erase(unique(begin(c), end(c), comp), end(c));
    return c;
}

template <typename T, typename Compare = less<T>>
T &chmin(T &l, T r, Compare &&f = less<T>()) { return l = min(l, r, f); }
template <typename T, typename Compare = less<T>>
T &chmax(T &l, T r, Compare &&f = less<T>()) { return l = max(l, r, f); }

template <typename F>
constexpr auto fix(F &&f) noexcept {
    return [f = std::tuple<F>(std::forward<F>(f))](auto &&...args) mutable {
        return std::get<0>(f)(fix(std::get<0>(f)), std::forward<decltype(args)>(args)...);
    };
}

#include <atcoder/dsu>

int main() {
    int n; cin >> n;

    auto g = vec<int>(uns, n, 0);
    auto e = vec<array<int, 2>>(uns, n);
    for (auto &[a, b] : e) {
        cin >> a >> b; --a; --b;
        g[a].push_back(b);
        g[b].push_back(a);
    }

    auto h = vec<int>(uns, n, 0);

    int sa = -1, sb = -1;

    atcoder::dsu dsu(n);
    for (auto [a, b] : e) {
        if (dsu.same(a, b)) {
            sa = a; sb = b;
            continue;
        }
        dsu.merge(a, b);
        h[a].push_back(b);
        h[b].push_back(a);
    }

    map<tuple<int, int>, bool> d;

    fix([&](auto f, int v, int p = -1) -> void {
        if (p != -1) {
            d[{ v, p }] = true;
        }

        for (auto u : h[v]) {
            if (u == p) {
                continue;
            }
            f(u, v);
        }
    })(sa);

    d[{ sa, sb }] = true;

    for (auto &[a, b] : e) {
        if (d[{ a, b }]) {
            cout << "->" << '\n';
        }
        else {
            cout << "<-" << '\n';
        }
    }

    cout << flush;
}