結果

問題 No.1244 Black Segment
コンテスト
ユーザー kuhaku
提出日時 2023-09-17 13:42:24
言語 C++17(gcc12)
(gcc 12.3.0 + boost 1.87.0)
結果
AC  
実行時間 50 ms / 2,000 ms
コード長 9,680 bytes
コンパイル時間 10,641 ms
コンパイル使用メモリ 296,560 KB
最終ジャッジ日時 2025-02-16 23:11:22
ジャッジサーバーID
（参考情報） 		judge2 / judge3
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 3
other AC * 36
権限があれば一括ダウンロードができます

ソースコード

diff # 

#line 1 "a.cpp"
#define PROBLEM ""
#line 2 "/home/kuhaku/atcoder/github/algo/lib/template/template.hpp"
#pragma GCC target("sse4.2,avx2,bmi2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
template <class T, class U>
bool chmax(T &a, const U &b) {
    return a < (T)b ? a = (T)b, true : false;
}
template <class T, class U>
bool chmin(T &a, const U &b) {
    return (T)b < a ? a = (T)b, true : false;
}
constexpr std::int64_t INF = 1000000000000000003;
constexpr int Inf = 1000000003;
constexpr int MOD = 1000000007;
constexpr int MOD_N = 998244353;
constexpr double EPS = 1e-7;
constexpr double PI = M_PI;
#line 3 "/home/kuhaku/atcoder/github/algo/lib/graph/graph.hpp"

/**
 * @brief 重み付きグラフ
 *
 * @tparam T 辺の重みの型
 */
template <class T>
struct Graph {
  private:
    struct _edge {
        constexpr _edge() : _from(), _to(), _weight() {}
        constexpr _edge(int from, int to, T weight) : _from(from), _to(to), _weight(weight) {}
        constexpr bool operator<(const _edge &rhs) const { return this->weight() < rhs.weight(); }
        constexpr bool operator>(const _edge &rhs) const { return rhs < *this; }

        constexpr int from() const { return this->_from; }
        constexpr int to() const { return this->_to; }
        constexpr T weight() const { return this->_weight; }

      private:
        int _from, _to;
        T _weight;
    };

  public:
    using edge_type = typename Graph<T>::_edge;

    Graph() : _size(), edges() {}
    Graph(int v) : _size(v), edges(v) {}

    const auto &operator[](int i) const { return this->edges[i]; }
    auto &operator[](int i) { return this->edges[i]; }
    const auto begin() const { return this->edges.begin(); }
    auto begin() { return this->edges.begin(); }
    const auto end() const { return this->edges.end(); }
    auto end() { return this->edges.end(); }
    constexpr int size() const { return this->_size; }

    void add_edge(const edge_type &e) { this->edges[e.from()].emplace_back(e); }
    void add_edge(int from, int to, T weight = T(1)) {
        this->edges[from].emplace_back(from, to, weight);
    }
    void add_edges(int from, int to, T weight = T(1)) {
        this->edges[from].emplace_back(from, to, weight);
        this->edges[to].emplace_back(to, from, weight);
    }

    void input_edge(int m, int base = 1) {
        for (int i = 0; i < m; ++i) {
            int from, to;
            T weight;
            std::cin >> from >> to >> weight;
            this->add_edge(from - base, to - base, weight);
        }
    }
    void input_edges(int m, int base = 1) {
        for (int i = 0; i < m; ++i) {
            int from, to;
            T weight;
            std::cin >> from >> to >> weight;
            this->add_edges(from - base, to - base, weight);
        }
    }

  private:
    int _size;
    std::vector<std::vector<edge_type>> edges;
};

template <>
struct Graph<void> {
  private:
    struct _edge {
        constexpr _edge() : _from(), _to() {}
        constexpr _edge(int from, int to) : _from(from), _to(to) {}

        constexpr int from() const { return this->_from; }
        constexpr int to() const { return this->_to; }
        constexpr int weight() const { return 1; }
        constexpr bool operator<(const _edge &rhs) const { return this->weight() < rhs.weight(); }
        constexpr bool operator>(const _edge &rhs) const { return rhs < *this; }

      private:
        int _from, _to;
    };

  public:
    using edge_type = typename Graph<void>::_edge;

    Graph() : _size(), edges() {}
    Graph(int v) : _size(v), edges(v) {}

    const auto &operator[](int i) const { return this->edges[i]; }
    auto &operator[](int i) { return this->edges[i]; }
    const auto begin() const { return this->edges.begin(); }
    auto begin() { return this->edges.begin(); }
    const auto end() const { return this->edges.end(); }
    auto end() { return this->edges.end(); }
    constexpr int size() const { return this->_size; }

    void add_edge(const edge_type &e) { this->edges[e.from()].emplace_back(e); }
    void add_edge(int from, int to) { this->edges[from].emplace_back(from, to); }
    void add_edges(int from, int to) {
        this->edges[from].emplace_back(from, to);
        this->edges[to].emplace_back(to, from);
    }

    void input_edge(int m, int base = 1) {
        for (int i = 0; i < m; ++i) {
            int from, to;
            std::cin >> from >> to;
            this->add_edge(from - base, to - base);
        }
    }
    void input_edges(int m, int base = 1) {
        for (int i = 0; i < m; ++i) {
            int from, to;
            std::cin >> from >> to;
            this->add_edges(from - base, to - base);
        }
    }

  private:
    int _size;
    std::vector<std::vector<edge_type>> edges;
};
#line 4 "/home/kuhaku/atcoder/github/algo/lib/graph/dijkstra.hpp"

/**
 * @brief ダイクストラ法
 *
 * @tparam T 辺の重みの型
 * @param g グラフ
 * @param s 始点
 * @param inf 正の無限表現
 * @retval std::vector<T> 各頂点までの最短距離
 */
template <class T>
std::vector<T> dijkstra(const Graph<T> &g, int s = 0, T inf = std::numeric_limits<T>::max()) {
    struct _node {
        constexpr _node() : _to(), _dist() {}
        constexpr _node(int to, T dist) : _to(to), _dist(dist) {}
        constexpr bool operator<(const _node &rhs) const { return this->dist() < rhs.dist(); }
        constexpr bool operator>(const _node &rhs) const { return rhs < *this; }

        constexpr int to() const { return this->_to; }
        constexpr T dist() const { return this->_dist; }

      private:
        int _to;
        T _dist;
    };
    std::vector<T> dists(g.size(), inf);
    std::priority_queue<_node, std::vector<_node>, std::greater<>> p_que;
    dists[s] = T();
    p_que.emplace(s, T());
    while (!p_que.empty()) {
        auto node = p_que.top();
        p_que.pop();
        if (dists[node.to()] < node.dist()) continue;
        for (auto &e : g[node.to()]) {
            if (chmin(dists[e.to()], node.dist() + e.weight()))
                p_que.emplace(e.to(), node.dist() + e.weight());
        }
    }
    return dists;
}

std::vector<int> dijkstra(const Graph<void> &g, int s = 0,
                          int inf = std::numeric_limits<int>::max()) {
    std::vector<int> dists(g.size(), inf);
    std::queue<int> que;
    dists[s] = 0;
    que.emplace(s);
    while (!que.empty()) {
        auto index = que.front();
        que.pop();
        for (auto &e : g[index]) {
            if (chmin(dists[e.to()], dists[index] + 1)) que.emplace(e.to());
        }
    }
    return dists;
}
#line 3 "/home/kuhaku/atcoder/github/algo/lib/template/macro.hpp"
#define FOR(i, m, n) for (int i = (m); i < int(n); ++i)
#define FORR(i, m, n) for (int i = (m)-1; i >= int(n); --i)
#define FORL(i, m, n) for (int64_t i = (m); i < int64_t(n); ++i)
#define rep(i, n) FOR (i, 0, n)
#define repn(i, n) FOR (i, 1, n + 1)
#define repr(i, n) FORR (i, n, 0)
#define repnr(i, n) FORR (i, n + 1, 1)
#define all(s) (s).begin(), (s).end()
#line 3 "/home/kuhaku/atcoder/github/algo/lib/template/sonic.hpp"
struct Sonic {
    Sonic() {
        std::ios::sync_with_stdio(false);
        std::cin.tie(nullptr);
    }

    constexpr void operator()() const {}
} sonic;
#line 5 "/home/kuhaku/atcoder/github/algo/lib/template/atcoder.hpp"
using namespace std;
using ll = std::int64_t;
using ld = long double;
template <class T, class U>
std::istream &operator>>(std::istream &is, std::pair<T, U> &p) {
    return is >> p.first >> p.second;
}
template <class T>
std::istream &operator>>(std::istream &is, std::vector<T> &v) {
    for (T &i : v) is >> i;
    return is;
}
template <class T, class U>
std::ostream &operator<<(std::ostream &os, const std::pair<T, U> &p) {
    return os << '(' << p.first << ',' << p.second << ')';
}
template <class T>
std::ostream &operator<<(std::ostream &os, const std::vector<T> &v) {
    for (auto it = v.begin(); it != v.end(); ++it) {
        os << (it == v.begin() ? "" : " ") << *it;
    }
    return os;
}
template <class Head, class... Tail>
void co(Head &&head, Tail &&...tail) {
    if constexpr (sizeof...(tail) == 0) std::cout << head << '\n';
    else std::cout << head << ' ', co(std::forward<Tail>(tail)...);
}
template <class Head, class... Tail>
void ce(Head &&head, Tail &&...tail) {
    if constexpr (sizeof...(tail) == 0) std::cerr << head << '\n';
    else std::cerr << head << ' ', ce(std::forward<Tail>(tail)...);
}
template <typename T, typename... Args>
auto make_vector(T x, int arg, Args... args) {
    if constexpr (sizeof...(args) == 0) return std::vector<T>(arg, x);
    else return std::vector(arg, make_vector<T>(x, args...));
}
void setp(int n) {
    std::cout << std::fixed << std::setprecision(n);
}
void Yes(bool is_correct = true) {
    std::cout << (is_correct ? "Yes" : "No") << '\n';
}
void No(bool is_not_correct = true) {
    Yes(!is_not_correct);
}
void YES(bool is_correct = true) {
    std::cout << (is_correct ? "YES" : "NO") << '\n';
}
void NO(bool is_not_correct = true) {
    YES(!is_not_correct);
}
void Takahashi(bool is_correct = true) {
    std::cout << (is_correct ? "Takahashi" : "Aoki") << '\n';
}
void Aoki(bool is_not_correct = true) {
    Takahashi(!is_not_correct);
}
#line 4 "a.cpp"

int main(void) {
    int n, m, a, b;
    cin >> n >> m >> a >> b;
    --a;
    Graph<int> g(n + 1);
    while (m--) {
        int u, v;
        cin >> u >> v;
        g.add_edges(u - 1, v, 1);
    }
    rep (i, a) g.add_edges(i, a, 0);
    FOR (i, b + 1, n + 1) g.add_edges(b, i, 0);
    int ans = dijkstra(g, a, Inf)[b];
    co(ans == Inf ? -1 : ans);

    return 0;
}
0