Test/LC/eulerian_trail_undirected.test.cpp

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Last update: 2025-05-27 19:35:07+09:00
Problem: https://judge.yosupo.jp/problem/eulerian_trail_undirected

Depends on

Code

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

#include "../../Src/Graph/EulerianTrail.hpp"
using namespace zawa;

#include <iostream>
#include <utility>
#include <vector>

void solve() {
    int N, M;
    std::cin >> N >> M;
    std::vector<std::pair<int, int>> E(M);
    for (auto& [u, v] : E) std::cin >> u >> v;
    auto ans = EulerianTrail(N, E, false);
    if (ans) {
        std::cout << "Yes\n";
        auto [vs, es] = std::move(*ans);
        for (int i = 0 ; i < std::ssize(vs) ; i++) std::cout << vs[i] << (i + 1 == std::ssize(vs) ? "" : " ");
        std::cout << '\n';
        for (int i = 0 ; i < std::ssize(es) ; i++) std::cout << es[i] << (i + 1 == std::ssize(es) ? "" : " ");
        std::cout << '\n';
    }
    else {
        std::cout << "No\n";
    }
}

int main() {
    std::cin.tie(nullptr);
    std::cout.tie(nullptr);
    std::ios::sync_with_stdio(false);
    int T;
    std::cin >> T;
    while (T--) {
        solve();
    }
}

#line 1 "Test/LC/eulerian_trail_undirected.test.cpp"
#define PROBLEM "https://judge.yosupo.jp/problem/eulerian_trail_undirected"

#line 2 "Src/Graph/EulerianTrail.hpp"

#include <algorithm>
#include <cassert>
#include <optional>
#include <utility>
#include <vector>

#line 2 "Src/Template/TypeAlias.hpp"

#include <cstdint>
#include <cstddef>

namespace zawa {

using i16 = std::int16_t;
using i32 = std::int32_t;
using i64 = std::int64_t;
using i128 = __int128_t;

using u8 = std::uint8_t;
using u16 = std::uint16_t;
using u32 = std::uint32_t;
using u64 = std::uint64_t;

using usize = std::size_t;

} // namespace zawa
#line 10 "Src/Graph/EulerianTrail.hpp"

namespace zawa {

// first: 頂点列, second: 辺番号列
template <class T>
std::optional<std::pair<std::vector<T>, std::vector<usize>>> EulerianTrail(usize n, const std::vector<std::pair<T, T>>& edges, bool directed) {
    std::vector<std::vector<std::pair<T, usize>>> g(n);
    for (usize i = 0 ; auto [u, v] : edges) {
        assert(u < n);
        assert(v < n);
        g[u].push_back({v, i});
        if (!directed) g[v].push_back({u, i});
        i++;
    }
    std::vector<bool> used(edges.size());
    std::vector<usize> cur(n), es;
    std::vector<T> vs;
    es.reserve(edges.size());
    vs.reserve(edges.size() + 1);
    auto dfs = [&](auto dfs, const T v) -> void {
        while (cur[v] < g[v].size()) {
            auto [x, i] = g[v][cur[v]++];
            if (!used[i]) {
                used[i] = true;
                dfs(dfs, x);
                es.push_back(i);
                vs.push_back(v);
            }
        }
    };
    usize st = edges.size() ? edges[0].first : 0, go = st;
    if (directed) {
        std::vector<usize> deg(n);
        for (auto [u, v] : edges) {
            deg[u]++;
            deg[v]--;
        }
        const usize p1 = 1, m1 = static_cast<usize>(-1);
        bool fnst = false, fngo = false;
        for (usize i = 0 ; i < n ; i++) {
            if (deg[i] == p1) {
                if (fnst) return std::nullopt;
                fnst = true;
                st = i;
            }
            else if (deg[i] == m1) {
                if (fngo) return std::nullopt;
                fngo = true;
                go = i;
            }
            else if (deg[i]) return std::nullopt;
        }
    }
    else {
        usize cntOdd = 0;
        for (usize i = 0 ; i < n ; i++) if (g[i].size() & 1) {
            if (cntOdd++) go = i;
            else st = i;
        }
        if (cntOdd != 0 and cntOdd != 2) return std::nullopt;
    }
    if (n) {
        dfs(dfs, st);
        std::ranges::reverse(vs);
        vs.push_back(go);
        std::ranges::reverse(es);
    }
    if (edges.size() != es.size()) return std::nullopt;
    return std::make_pair(vs, es);
}

} // namespace zawa
#line 4 "Test/LC/eulerian_trail_undirected.test.cpp"
using namespace zawa;

#include <iostream>
#line 9 "Test/LC/eulerian_trail_undirected.test.cpp"

void solve() {
    int N, M;
    std::cin >> N >> M;
    std::vector<std::pair<int, int>> E(M);
    for (auto& [u, v] : E) std::cin >> u >> v;
    auto ans = EulerianTrail(N, E, false);
    if (ans) {
        std::cout << "Yes\n";
        auto [vs, es] = std::move(*ans);
        for (int i = 0 ; i < std::ssize(vs) ; i++) std::cout << vs[i] << (i + 1 == std::ssize(vs) ? "" : " ");
        std::cout << '\n';
        for (int i = 0 ; i < std::ssize(es) ; i++) std::cout << es[i] << (i + 1 == std::ssize(es) ? "" : " ");
        std::cout << '\n';
    }
    else {
        std::cout << "No\n";
    }
}

int main() {
    std::cin.tie(nullptr);
    std::cout.tie(nullptr);
    std::ios::sync_with_stdio(false);
    int T;
    std::cin >> T;
    while (T--) {
        solve();
    }
}