結果

問題 No.1774 Love Triangle (Hard)
ユーザー hitonanode
提出日時 2021-10-11 23:25:58
言語 C++17(clang)
(17.0.6 + boost 1.87.0)
結果
AC  
実行時間 7,192 ms / 8,000 ms
コード長 5,490 bytes
コンパイル時間 4,189 ms
コンパイル使用メモリ 152,992 KB
実行使用メモリ 10,412 KB
最終ジャッジ日時 2024-09-17 07:48:04
合計ジャッジ時間 493,667 ms
ジャッジサーバーID
（参考情報） 		judge3 / judge5
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 * 90
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 # 

#include <algorithm>
#include <cassert>
#include <chrono>
#include <iostream>
#include <numeric>
#include <random>
#include <utility>
#include <vector>
using namespace std;

#include <atcoder/modint>
using mint = atcoder::static_modint<(1 << 30) + 3>;  // prime


template <class T>
std::vector<T> mat_vec_mul(const std::vector<std::vector<T>> &mat, const std::vector<T> &vec) {
    int H = mat.size(), W = mat[0].size();
    assert(W == int(vec.size()));
    std::vector<T> ret(H);
    for (int i = 0; i < H; ++i) {
        for (int j = 0; j < W; ++j) ret[i] += mat[i][j] * vec[j];
    }
    return ret;
}

// Try to calculate inverse of M and return rank of M (destructive)
template <class T>
int inverse_matrix(std::vector<std::vector<T>> &M) {
    const int N = M.size();
    assert(N and M[0].size() == M.size());
    std::vector<std::vector<T>> ret(N, std::vector<T>(N));
    for (int i = 0; i < N; ++i) ret[i][i] = 1;

    int rank = 0;
    for (int i = 0; i < N; ++i) {
        int ti = i;
        while (ti < N and M[ti][i] == 0) ti++;
        if (ti == N) {
            continue;
        }
        ++rank;
        ret[i].swap(ret[ti]), M[i].swap(M[ti]);
        T inv = T(1) / M[i][i];
        for (int j = 0; j < N; ++j) ret[i][j] *= inv;
        for (int j = i + 1; j < N; ++j) M[i][j] *= inv;
        for (int h = 0; h < N; ++h) {
            if (i == h) continue;
            const T c = -M[h][i];
            for (int j = 0; j < N; ++j) ret[h][j] += ret[i][j] * c;
            for (int j = i + 1; j < N; ++j) M[h][j] += M[i][j] * c;
        }
    }
    M = ret;
    return rank;
}


template <class ModInt>
std::vector<int>
linear_matroid_parity(const std::vector<std::pair<std::vector<ModInt>, std::vector<ModInt>>> &bcs) {
    if (bcs.empty()) return {};
    const int r = bcs[0].first.size(), m = bcs.size(), r2 = (r + 1) / 2;
    std::mt19937 mt(std::chrono::steady_clock::now().time_since_epoch().count());
    std::uniform_int_distribution<int> d(0, ModInt::mod() - 1);

    auto gen_random_vector = [&]() -> std::vector<ModInt> {
        std::vector<ModInt> v(r2 * 2);
        for (int i = 0; i < r2 * 2; i++) v[i] = d(mt);
        return v;
    };

    std::vector<ModInt> x(m);
    std::vector<std::pair<vector<ModInt>, vector<ModInt>>> bcadd(r2);

    std::vector<std::vector<ModInt>> Yinv; // r2 * r2 matrices
    int rankY = -1;
    while (rankY < r2 * 2) {
        Yinv.assign(r2 * 2, std::vector<ModInt>(r2 * 2, 0));
        for (auto &[b, c] : bcadd) {
            b = gen_random_vector(), c = gen_random_vector();
            for (int j = 0; j < r2 * 2; j++) {
                for (int k = 0; k < r2 * 2; k++) Yinv[j][k] += b[j] * c[k] - c[j] * b[k];
            }
        }
        rankY = inverse_matrix(Yinv);
    }

    std::vector<std::vector<ModInt>> tmpmat(r2 * 2, std::vector<ModInt>(r2 * 2));


    std::vector<int> ret(m, -1);
    int additional_dim = bcadd.size();
    for (int i = 0; i < m; i++) {
        {
            x[i] = d(mt);
            auto b = bcs[i].first, c = bcs[i].second;
            b.resize(r2 * 2, 0), c.resize(r2 * 2, 0);
            std::vector<ModInt> Yib = mat_vec_mul(Yinv, b), Yic = mat_vec_mul(Yinv, c);
            ModInt bYic = std::inner_product(b.begin(), b.end(), Yic.begin(), ModInt(0));
            ModInt v = 1 + x[i] * bYic;

            if (v == 0) break; // failed

            const auto coeff = x[i] / v;
            for (int j = 0; j < r2 * 2; j++) {
                for (int k = 0; k < r2 * 2; k++) {
                    tmpmat[j][k] = Yib[j] * Yic[k] - Yic[j] * Yib[k];
                }
            }

            for (int j = 0; j < r2 * 2; j++) {
                for (int k = 0; k < r2 * 2; k++) Yinv[j][k] -= tmpmat[j][k] * coeff;
            }
        }

        if (additional_dim) {
            const auto &[b, c] = bcadd[additional_dim - 1];
            std::vector<ModInt> Yib = mat_vec_mul(Yinv, b), Yic = mat_vec_mul(Yinv, c);
            ModInt bYic = std::inner_product(b.begin(), b.end(), Yic.begin(), ModInt(0));
            const ModInt v = 1 + bYic;
            if (v != 0) {
                // 消しても正則
                additional_dim--;
                const auto coeff = 1 / v;
                for (int j = 0; j < r2 * 2; j++) {
                    for (int k = 0; k < r2 * 2; k++) tmpmat[j][k] = Yib[j] * Yic[k] - Yic[j] * Yib[k];
                }
                for (int j = 0; j < r2 * 2; j++) {
                    for (int k = 0; k < r2 * 2; k++) Yinv[j][k] -= tmpmat[j][k] * coeff;
                }
            }
        }

        ret[i] = r2 - additional_dim;
    }

    return ret;
}

vector<int> solve(int N, vector<pair<pair<int, int>, pair<int, int>>> bcs) {
    vector<pair<vector<mint>, vector<mint>>> vs;
    for (auto [ab, cd] : bcs) {
        auto [a, b] = ab;
        auto [c, d] = cd;
        vector<mint> B(N), C(N);
        B.at(a) += 1;
        B.at(b) -= 1;
        C.at(c) += 1;
        C.at(d) -= 1;
        vs.emplace_back(B, C);
    }

    auto ret = linear_matroid_parity<mint>(vs);
    auto ret2 = linear_matroid_parity<mint>(vs);
    for (int i = 0; i < int(ret.size()); i++) ret[i] = max(ret[i], ret2[i]);
    return ret;
}

int main() {
    int N, M;
    cin >> N >> M;
    vector<pair<pair<int, int>, pair<int, int>>> edges;
    while (M--) {
        int u, v, w;
        cin >> u >> v >> w;
        u--, v--, w--;
        edges.push_back({{u, w}, {v, w}});
    }
    auto ret = solve(N, edges);
    for (auto x : ret) cout << x << '\n';
}
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