Library

This documentation is automatically generated by online-judge-tools/verification-helper

View the Project on GitHub ebi-fly13/Library

:heavy_check_mark: test/graph/Directed_MST.test.cpp

Depends on

Code

#define PROBLEM "https://judge.yosupo.jp/problem/directedmst"

#include "../../graph/directed_mst.hpp"

#include "../../template/template.hpp"

namespace ebi {

void main_() {
    int n, m, s;
    std::cin >> n >> m >> s;
    Graph<i64> g(n);
    g.read_graph(m, 0, true, true);
    auto res = directed_mst(s, g);
    if (res) {
        auto [x, p] = res.value();
        std::cout << x << '\n';
        std::cout << p << '\n';
    } else {
        std::cout << "-1\n";
    }
}

}  // namespace ebi

int main() {
    ebi::fast_io();
    int t = 1;
    // std::cin >> t;
    while (t--) {
        ebi::main_();
    }
    return 0;
}
#line 1 "test/graph/Directed_MST.test.cpp"
#define PROBLEM "https://judge.yosupo.jp/problem/directedmst"

#line 2 "graph/directed_mst.hpp"

#include <cassert>
#include <numeric>
#include <optional>
#include <ranges>
#include <utility>
#include <vector>

#line 2 "data_structure/skew_heap.hpp"

#line 4 "data_structure/skew_heap.hpp"
#include <functional>
#include <memory>
#line 7 "data_structure/skew_heap.hpp"

namespace ebi {

template <class Key, class T, class Compare = std::less<Key>> struct skew_heap {
  private:
    using value_type = Key;
    using Self = skew_heap<Key, T, Compare>;

    struct Node;
    using iterator = std::shared_ptr<Node>;

    struct Node {
        Node(value_type x_, T info_) : x(x_), info(info_) {}

        void propagate() {
            if (lhs) lhs->lazy += lazy;
            if (rhs) rhs->lazy += lazy;
            x += lazy;
            lazy = value_type();
        }

        value_type x;
        T info;
        value_type lazy = value_type();
        iterator lhs = nullptr, rhs = nullptr;
    };

    iterator internal_meld(iterator lhs, iterator rhs) {
        if (lhs == nullptr) return rhs;
        if (rhs == nullptr) return lhs;
        lhs->propagate();
        rhs->propagate();
        if (Compare()(lhs->x, rhs->x)) {
            std::swap(lhs, rhs);
        }
        lhs->rhs = internal_meld(lhs->rhs, rhs);
        std::swap(lhs->lhs, lhs->rhs);
        return lhs;
    }

  public:
    skew_heap() = default;

    void push(value_type x, T info) {
        root = internal_meld(root, std::make_shared<Node>(x, info));
        sz++;
    }

    void pop() {
        assert(!empty());
        root = internal_meld(root->lhs, root->rhs);
        sz--;
    }

    void meld(Self &heap) {
        root = internal_meld(root, heap.root);
        sz += heap.sz;
    }

    void add(value_type lazy) {
        if (root == nullptr) return;
        root->lazy += lazy;
        root->propagate();
    }

    bool empty() const {
        return root == nullptr;
    }

    std::pair<value_type, T> top() const {
        return {root->x, root->info};
    }

    int size() const {
        return sz;
    }

  private:
    iterator root = nullptr;
    int sz = 0;
};

}  // namespace ebi
#line 2 "graph/base.hpp"

#line 4 "graph/base.hpp"
#include <iostream>
#line 7 "graph/base.hpp"

#line 2 "data_structure/simple_csr.hpp"

#line 6 "data_structure/simple_csr.hpp"

namespace ebi {

template <class E> struct simple_csr {
    simple_csr() = default;

    simple_csr(int n, const std::vector<std::pair<int, E>>& elements)
        : start(n + 1, 0), elist(elements.size()) {
        for (auto e : elements) {
            start[e.first + 1]++;
        }
        for (auto i : std::views::iota(0, n)) {
            start[i + 1] += start[i];
        }
        auto counter = start;
        for (auto [i, e] : elements) {
            elist[counter[i]++] = e;
        }
    }

    simple_csr(const std::vector<std::vector<E>>& es)
        : start(es.size() + 1, 0) {
        int n = es.size();
        for (auto i : std::views::iota(0, n)) {
            start[i + 1] = (int)es[i].size() + start[i];
        }
        elist.resize(start.back());
        for (auto i : std::views::iota(0, n)) {
            std::copy(es[i].begin(), es[i].end(), elist.begin() + start[i]);
        }
    }

    int size() const {
        return (int)start.size() - 1;
    }

    const auto operator[](int i) const {
        return std::ranges::subrange(elist.begin() + start[i],
                                     elist.begin() + start[i + 1]);
    }
    auto operator[](int i) {
        return std::ranges::subrange(elist.begin() + start[i],
                                     elist.begin() + start[i + 1]);
    }

    const auto operator()(int i, int l, int r) const {
        return std::ranges::subrange(elist.begin() + start[i] + l,
                                     elist.begin() + start[i + 1] + r);
    }
    auto operator()(int i, int l, int r) {
        return std::ranges::subrange(elist.begin() + start[i] + l,
                                     elist.begin() + start[i + 1] + r);
    }

  private:
    std::vector<int> start;
    std::vector<E> elist;
};

}  // namespace ebi
#line 9 "graph/base.hpp"

namespace ebi {

template <class T> struct Edge {
    int from, to;
    T cost;
    int id;
};

template <class E> struct Graph {
    using cost_type = E;
    using edge_type = Edge<cost_type>;

    Graph(int n_) : n(n_) {}

    Graph() = default;

    void add_edge(int u, int v, cost_type c) {
        buff.emplace_back(u, edge_type{u, v, c, m});
        edges.emplace_back(edge_type{u, v, c, m++});
    }

    void add_undirected_edge(int u, int v, cost_type c) {
        buff.emplace_back(u, edge_type{u, v, c, m});
        buff.emplace_back(v, edge_type{v, u, c, m});
        edges.emplace_back(edge_type{u, v, c, m});
        m++;
    }

    void read_tree(int offset = 1, bool is_weighted = false) {
        read_graph(n - 1, offset, false, is_weighted);
    }

    void read_parents(int offset = 1) {
        for (auto i : std::views::iota(1, n)) {
            int p;
            std::cin >> p;
            p -= offset;
            add_undirected_edge(p, i, 1);
        }
        build();
    }

    void read_graph(int e, int offset = 1, bool is_directed = false,
                    bool is_weighted = false) {
        for (int i = 0; i < e; i++) {
            int u, v;
            std::cin >> u >> v;
            u -= offset;
            v -= offset;
            if (is_weighted) {
                cost_type c;
                std::cin >> c;
                if (is_directed) {
                    add_edge(u, v, c);
                } else {
                    add_undirected_edge(u, v, c);
                }
            } else {
                if (is_directed) {
                    add_edge(u, v, 1);
                } else {
                    add_undirected_edge(u, v, 1);
                }
            }
        }
        build();
    }

    void build() {
        assert(!prepared);
        csr = simple_csr<edge_type>(n, buff);
        buff.clear();
        prepared = true;
    }

    int size() const {
        return n;
    }

    int node_number() const {
        return n;
    }

    int edge_number() const {
        return m;
    }

    edge_type get_edge(int i) const {
        return edges[i];
    }

    std::vector<edge_type> get_edges() const {
        return edges;
    }

    const auto operator[](int i) const {
        return csr[i];
    }
    auto operator[](int i) {
        return csr[i];
    }

  private:
    int n, m = 0;

    std::vector<std::pair<int,edge_type>> buff;

    std::vector<edge_type> edges;
    simple_csr<edge_type> csr;
    bool prepared = false;
};

}  // namespace ebi
#line 12 "graph/directed_mst.hpp"

namespace ebi {

namespace internal {

struct union_find_not_merge_tech {
  public:
    union_find_not_merge_tech(int n_) : n(n_), data(n, -1) {}

    int leader(int u) {
        if (data[u] < 0) return u;
        return data[u] = leader(data[u]);
    }

    bool merge(int u, int v) {
        u = leader(u);
        v = leader(v);
        if (u == v) return false;
        data[u] += data[v];
        data[v] = u;
        return true;
    }

    bool same(int u, int v) {
        return leader(u) == leader(v);
    }

    int size(int u) {
        u = leader(u);
        return -data[u];
    }

  private:
    int n;
    std::vector<int> data;
};

}  // namespace internal

template <class T>
std::optional<std::pair<T, std::vector<int>>> directed_mst(int root,
                                                           const Graph<T> &g) {
    using Heap = skew_heap<T, Edge<T>, std::greater<T>>;
    int n = g.node_number();
    std::vector<int> used(2 * n, 0);
    std::vector<int> par_node(2 * n, -1);
    std::vector<int> best_id(2 * n, -1);
    std::vector<T> best_cost(2 * n);
    internal::union_find_not_merge_tech uf(2 * n);
    std::vector<Heap> heap(2 * n);
    int nxt = n;
    used[root] = 2;
    for (auto e : g.get_edges()) {
        heap[e.to].push(e.cost, e);
    }
    T sum = 0;
    for (auto s : std::views::iota(0, n)) {
        if (used[s]) continue;
        std::vector<int> path = {s};
        while (1) {
            int a = path.back();
            if (heap[a].empty()) return std::nullopt;
            auto [c, e] = heap[a].top();
            heap[a].pop();
            int v = uf.leader(e.from);
            if (a == v) continue;
            used[a] = 1;
            best_id[a] = e.id;
            best_cost[a] = c;
            sum += c;
            if (!used[v]) {
                path.emplace_back(v);
                continue;
            } else if (used[v] == 1) {
                int w = -1;
                int u = nxt++;
                while (w != v) {
                    w = path.back();
                    path.pop_back();
                    T sub = best_cost[w];
                    heap[w].add(-sub);
                    heap[u].meld(heap[w]);
                    par_node[w] = u;
                    uf.merge(u, w);
                    used[w] = 2;
                }
                path.emplace_back(u);
            } else
                break;
        }
        for (auto v : path) used[v] = 2;
    }
    std::vector<int> par(n, -1);
    std::vector<bool> done(nxt, false);
    done[root] = true;
    par[root] = root;
    T ret = 0;
    for (auto i : std::views::iota(0, nxt) | std::views::reverse) {
        if (done[i]) continue;
        int id = best_id[i];
        auto e = g.get_edge(id);
        par[e.to] = e.from;
        ret += e.cost;
        int x = e.to;
        while (x != -1 && !done[x]) {
            done[x] = true;
            x = par_node[x];
        }
    }
    assert(sum == ret);
    return std::pair<T, std::vector<int>>{sum, par};
}

}  // namespace ebi
#line 4 "test/graph/Directed_MST.test.cpp"

#line 1 "template/template.hpp"
#include <bits/stdc++.h>

#define rep(i, a, n) for (int i = (int)(a); i < (int)(n); i++)
#define rrep(i, a, n) for (int i = ((int)(n)-1); i >= (int)(a); i--)
#define Rep(i, a, n) for (i64 i = (i64)(a); i < (i64)(n); i++)
#define RRep(i, a, n) for (i64 i = ((i64)(n)-i64(1)); i >= (i64)(a); i--)
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()

#line 2 "template/debug_template.hpp"

#line 4 "template/debug_template.hpp"

namespace ebi {

#ifdef LOCAL
#define debug(...)                                                      \
    std::cerr << "LINE: " << __LINE__ << "  [" << #__VA_ARGS__ << "]:", \
        debug_out(__VA_ARGS__)
#else
#define debug(...)
#endif

void debug_out() {
    std::cerr << std::endl;
}

template <typename Head, typename... Tail> void debug_out(Head h, Tail... t) {
    std::cerr << " " << h;
    if (sizeof...(t) > 0) std::cerr << " :";
    debug_out(t...);
}

}  // namespace ebi
#line 2 "template/int_alias.hpp"

#line 4 "template/int_alias.hpp"

namespace ebi {

using ld = long double;
using std::size_t;
using i8 = std::int8_t;
using u8 = std::uint8_t;
using i16 = std::int16_t;
using u16 = std::uint16_t;
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;

}  // namespace ebi
#line 2 "template/io.hpp"

#line 7 "template/io.hpp"

namespace ebi {

template <typename T1, typename T2>
std::ostream &operator<<(std::ostream &os, const std::pair<T1, T2> &pa) {
    return os << pa.first << " " << pa.second;
}

template <typename T1, typename T2>
std::istream &operator>>(std::istream &os, std::pair<T1, T2> &pa) {
    return os >> pa.first >> pa.second;
}

template <typename T>
std::ostream &operator<<(std::ostream &os, const std::vector<T> &vec) {
    for (std::size_t i = 0; i < vec.size(); i++)
        os << vec[i] << (i + 1 == vec.size() ? "" : " ");
    return os;
}

template <typename T>
std::istream &operator>>(std::istream &os, std::vector<T> &vec) {
    for (T &e : vec) std::cin >> e;
    return os;
}

template <typename T>
std::ostream &operator<<(std::ostream &os, const std::optional<T> &opt) {
    if (opt) {
        os << opt.value();
    } else {
        os << "invalid value";
    }
    return os;
}

void fast_io() {
    std::cout << std::fixed << std::setprecision(15);
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);
}

}  // namespace ebi
#line 2 "template/utility.hpp"

#line 5 "template/utility.hpp"

#line 8 "template/utility.hpp"

namespace ebi {

template <class T> inline bool chmin(T &a, T b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}

template <class T> inline bool chmax(T &a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

template <class T> T safe_ceil(T a, T b) {
    if (a % b == 0)
        return a / b;
    else if (a >= 0)
        return (a / b) + 1;
    else
        return -((-a) / b);
}

template <class T> T safe_floor(T a, T b) {
    if (a % b == 0)
        return a / b;
    else if (a >= 0)
        return a / b;
    else
        return -((-a) / b) - 1;
}

constexpr i64 LNF = std::numeric_limits<i64>::max() / 4;

constexpr int INF = std::numeric_limits<int>::max() / 2;

const std::vector<int> dy = {1, 0, -1, 0, 1, 1, -1, -1};
const std::vector<int> dx = {0, 1, 0, -1, 1, -1, 1, -1};

}  // namespace ebi
#line 6 "test/graph/Directed_MST.test.cpp"

namespace ebi {

void main_() {
    int n, m, s;
    std::cin >> n >> m >> s;
    Graph<i64> g(n);
    g.read_graph(m, 0, true, true);
    auto res = directed_mst(s, g);
    if (res) {
        auto [x, p] = res.value();
        std::cout << x << '\n';
        std::cout << p << '\n';
    } else {
        std::cout << "-1\n";
    }
}

}  // namespace ebi

int main() {
    ebi::fast_io();
    int t = 1;
    // std::cin >> t;
    while (t--) {
        ebi::main_();
    }
    return 0;
}
Back to top page