cplib-cpp

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:heavy_check_mark: graph/test/enumerate_cliques.test.cpp

Depends on

Code

#include "../enumerate_cliques.hpp"
#include "../../modint.hpp"
#include <iostream>
#include <vector>
using namespace std;

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

int main() {
    cin.tie(nullptr), ios::sync_with_stdio(false);

    int N, M;
    cin >> N >> M;
    using mint = ModInt998244353;
    vector<mint> X(N);
    for (auto &x : X) cin >> x;

    enumerate_cliques ec(N);
    while (M--) {
        int u, v;
        cin >> u >> v;
        ec.add_bi_edge(u, v);
    }
    mint ret = mint();

    auto op = [&](const std::vector<int> &clique) -> void {
        mint tmp = 1;
        for (int x : clique) tmp *= X.at(x);
        ret += tmp;
    };
    ec.run(op);

    cout << ret << endl;
}
#line 2 "graph/enumerate_cliques.hpp"

/**
 * @file enumerate_cliques.hpp
 * @brief Enumerate all cliques of given undirected graph
 * @author hitonanode
 * @date 2023/03/10
 */

#include <algorithm>
#include <cassert>
#include <numeric>
#include <queue>
#include <utility>
#include <vector>

// Complexity: O(2^sqrt(2m) * n)
// Verify: https://judge.yosupo.jp/problem/enumerate_cliques (~1ms for n <= 100, m <= 100)
// p.15, https://www.slideshare.net/wata_orz/ss-12131479
struct enumerate_cliques {
    std::vector<std::vector<int>> to;
    std::vector<std::pair<int, int>> edges;

    int n() const { return to.size(); }
    int m() const { return edges.size(); }

    enumerate_cliques(int n_) : to(n_) {}

    void add_bi_edge(int u, int v) {
        assert(0 <= u and u < n());
        assert(0 <= v and v < n());
        if (u != v) edges.emplace_back(std::minmax(u, v));
    }

    // Build `to`
    void precalc() {
        std::sort(edges.begin(), edges.end());
        edges.erase(std::unique(edges.begin(), edges.end()), edges.end());

        for (auto &vec : to) vec.clear();
        for (auto [u, v] : edges) to.at(u).push_back(v), to.at(v).push_back(u);
        for (auto &vec : to) std::sort(vec.begin(), vec.end());
    }

    template <class F>
    void bruteforce(const std::vector<int> &cand_vs, int prefix_use, F op) const {
        const int k = cand_vs.size();
        const int mask_all = (1 << k) - 1;
        std::vector<int> ok_masks(k, mask_all);

        for (int i = 0; i < k; ++i) {
            for (int j = 0; j < i; ++j) {
                int u = cand_vs.at(i), v = cand_vs.at(j);
                if (!std::binary_search(to.at(u).cbegin(), to.at(u).cend(), v)) {
                    ok_masks.at(i) &= ~(1 << j), ok_masks.at(j) &= ~(1 << i);
                }
            }
        }

        std::vector<int> seq;
        if (prefix_use >= 0) seq.push_back(prefix_use);
        seq.reserve(seq.size() + k);

        auto rec = [&](auto &&self, int now, const int last_mask) -> void {
            op(seq);
            seq.push_back(-1);
            for (int i = now; i < k; ++i) {
                if ((last_mask >> i) & 1) {
                    seq.back() = cand_vs.at(i);
                    self(self, i + 1, last_mask & ok_masks.at(i));
                }
            }
            seq.pop_back();
        };
        rec(rec, 0, mask_all);
        return;
    }

    template <class F> void run(F op) {
        precalc();

        std::vector<int> deg(n()), is_alive(n(), 1);
        using P = std::pair<int, int>;
        std::priority_queue<P, std::vector<P>, std::greater<P>> pq;
        for (int i = 0; i < n(); ++i) deg.at(i) = to.at(i).size(), pq.emplace(deg.at(i), i);

        int rem_n = n(), rem_m = m();

        std::vector<int> cand_vs;
        while (!pq.empty()) {
            auto [di, i] = pq.top();
            pq.pop();
            if (deg.at(i) != di) continue;

            cand_vs.clear();

            if (di * di > rem_m * 2) { // Avoid "deg[i] = 0" case
                for (int i = 0; i < n(); ++i) {
                    if (is_alive.at(i)) cand_vs.push_back(i);
                }
                bruteforce(cand_vs, -1, op);
                break;
            }

            for (int j : to.at(i)) {
                if (is_alive.at(j)) cand_vs.push_back(j);
            }
            bruteforce(cand_vs, i, op);

            --rem_n, deg.at(i) = 0, is_alive.at(i) = 0;
            for (int j : cand_vs) --rem_m, --deg.at(j), pq.emplace(deg.at(j), j);
        }
    }
};
#line 3 "modint.hpp"
#include <iostream>
#include <set>
#line 6 "modint.hpp"

template <int md> struct ModInt {
    using lint = long long;
    constexpr static int mod() { return md; }
    static int get_primitive_root() {
        static int primitive_root = 0;
        if (!primitive_root) {
            primitive_root = [&]() {
                std::set<int> fac;
                int v = md - 1;
                for (lint i = 2; i * i <= v; i++)
                    while (v % i == 0) fac.insert(i), v /= i;
                if (v > 1) fac.insert(v);
                for (int g = 1; g < md; g++) {
                    bool ok = true;
                    for (auto i : fac)
                        if (ModInt(g).pow((md - 1) / i) == 1) {
                            ok = false;
                            break;
                        }
                    if (ok) return g;
                }
                return -1;
            }();
        }
        return primitive_root;
    }
    int val_;
    int val() const noexcept { return val_; }
    constexpr ModInt() : val_(0) {}
    constexpr ModInt &_setval(lint v) { return val_ = (v >= md ? v - md : v), *this; }
    constexpr ModInt(lint v) { _setval(v % md + md); }
    constexpr explicit operator bool() const { return val_ != 0; }
    constexpr ModInt operator+(const ModInt &x) const {
        return ModInt()._setval((lint)val_ + x.val_);
    }
    constexpr ModInt operator-(const ModInt &x) const {
        return ModInt()._setval((lint)val_ - x.val_ + md);
    }
    constexpr ModInt operator*(const ModInt &x) const {
        return ModInt()._setval((lint)val_ * x.val_ % md);
    }
    constexpr ModInt operator/(const ModInt &x) const {
        return ModInt()._setval((lint)val_ * x.inv().val() % md);
    }
    constexpr ModInt operator-() const { return ModInt()._setval(md - val_); }
    constexpr ModInt &operator+=(const ModInt &x) { return *this = *this + x; }
    constexpr ModInt &operator-=(const ModInt &x) { return *this = *this - x; }
    constexpr ModInt &operator*=(const ModInt &x) { return *this = *this * x; }
    constexpr ModInt &operator/=(const ModInt &x) { return *this = *this / x; }
    friend constexpr ModInt operator+(lint a, const ModInt &x) { return ModInt(a) + x; }
    friend constexpr ModInt operator-(lint a, const ModInt &x) { return ModInt(a) - x; }
    friend constexpr ModInt operator*(lint a, const ModInt &x) { return ModInt(a) * x; }
    friend constexpr ModInt operator/(lint a, const ModInt &x) { return ModInt(a) / x; }
    constexpr bool operator==(const ModInt &x) const { return val_ == x.val_; }
    constexpr bool operator!=(const ModInt &x) const { return val_ != x.val_; }
    constexpr bool operator<(const ModInt &x) const {
        return val_ < x.val_;
    } // To use std::map<ModInt, T>
    friend std::istream &operator>>(std::istream &is, ModInt &x) {
        lint t;
        return is >> t, x = ModInt(t), is;
    }
    constexpr friend std::ostream &operator<<(std::ostream &os, const ModInt &x) {
        return os << x.val_;
    }

    constexpr ModInt pow(lint n) const {
        ModInt ans = 1, tmp = *this;
        while (n) {
            if (n & 1) ans *= tmp;
            tmp *= tmp, n >>= 1;
        }
        return ans;
    }

    static constexpr int cache_limit = std::min(md, 1 << 21);
    static std::vector<ModInt> facs, facinvs, invs;

    constexpr static void _precalculation(int N) {
        const int l0 = facs.size();
        if (N > md) N = md;
        if (N <= l0) return;
        facs.resize(N), facinvs.resize(N), invs.resize(N);
        for (int i = l0; i < N; i++) facs[i] = facs[i - 1] * i;
        facinvs[N - 1] = facs.back().pow(md - 2);
        for (int i = N - 2; i >= l0; i--) facinvs[i] = facinvs[i + 1] * (i + 1);
        for (int i = N - 1; i >= l0; i--) invs[i] = facinvs[i] * facs[i - 1];
    }

    constexpr ModInt inv() const {
        if (this->val_ < cache_limit) {
            if (facs.empty()) facs = {1}, facinvs = {1}, invs = {0};
            while (this->val_ >= int(facs.size())) _precalculation(facs.size() * 2);
            return invs[this->val_];
        } else {
            return this->pow(md - 2);
        }
    }
    constexpr ModInt fac() const {
        while (this->val_ >= int(facs.size())) _precalculation(facs.size() * 2);
        return facs[this->val_];
    }
    constexpr ModInt facinv() const {
        while (this->val_ >= int(facs.size())) _precalculation(facs.size() * 2);
        return facinvs[this->val_];
    }
    constexpr ModInt doublefac() const {
        lint k = (this->val_ + 1) / 2;
        return (this->val_ & 1) ? ModInt(k * 2).fac() / (ModInt(2).pow(k) * ModInt(k).fac())
                                : ModInt(k).fac() * ModInt(2).pow(k);
    }

    constexpr ModInt nCr(int r) const {
        if (r < 0 or this->val_ < r) return ModInt(0);
        return this->fac() * (*this - r).facinv() * ModInt(r).facinv();
    }

    constexpr ModInt nPr(int r) const {
        if (r < 0 or this->val_ < r) return ModInt(0);
        return this->fac() * (*this - r).facinv();
    }

    static ModInt binom(int n, int r) {
        static long long bruteforce_times = 0;

        if (r < 0 or n < r) return ModInt(0);
        if (n <= bruteforce_times or n < (int)facs.size()) return ModInt(n).nCr(r);

        r = std::min(r, n - r);

        ModInt ret = ModInt(r).facinv();
        for (int i = 0; i < r; ++i) ret *= n - i;
        bruteforce_times += r;

        return ret;
    }

    // Multinomial coefficient, (k_1 + k_2 + ... + k_m)! / (k_1! k_2! ... k_m!)
    // Complexity: O(sum(ks))
    template <class Vec> static ModInt multinomial(const Vec &ks) {
        ModInt ret{1};
        int sum = 0;
        for (int k : ks) {
            assert(k >= 0);
            ret *= ModInt(k).facinv(), sum += k;
        }
        return ret * ModInt(sum).fac();
    }

    // Catalan number, C_n = binom(2n, n) / (n + 1)
    // C_0 = 1, C_1 = 1, C_2 = 2, C_3 = 5, C_4 = 14, ...
    // https://oeis.org/A000108
    // Complexity: O(n)
    static ModInt catalan(int n) {
        if (n < 0) return ModInt(0);
        return ModInt(n * 2).fac() * ModInt(n + 1).facinv() * ModInt(n).facinv();
    }

    ModInt sqrt() const {
        if (val_ == 0) return 0;
        if (md == 2) return val_;
        if (pow((md - 1) / 2) != 1) return 0;
        ModInt b = 1;
        while (b.pow((md - 1) / 2) == 1) b += 1;
        int e = 0, m = md - 1;
        while (m % 2 == 0) m >>= 1, e++;
        ModInt x = pow((m - 1) / 2), y = (*this) * x * x;
        x *= (*this);
        ModInt z = b.pow(m);
        while (y != 1) {
            int j = 0;
            ModInt t = y;
            while (t != 1) j++, t *= t;
            z = z.pow(1LL << (e - j - 1));
            x *= z, z *= z, y *= z;
            e = j;
        }
        return ModInt(std::min(x.val_, md - x.val_));
    }
};
template <int md> std::vector<ModInt<md>> ModInt<md>::facs = {1};
template <int md> std::vector<ModInt<md>> ModInt<md>::facinvs = {1};
template <int md> std::vector<ModInt<md>> ModInt<md>::invs = {0};

using ModInt998244353 = ModInt<998244353>;
// using mint = ModInt<998244353>;
// using mint = ModInt<1000000007>;
#line 5 "graph/test/enumerate_cliques.test.cpp"
using namespace std;

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

int main() {
    cin.tie(nullptr), ios::sync_with_stdio(false);

    int N, M;
    cin >> N >> M;
    using mint = ModInt998244353;
    vector<mint> X(N);
    for (auto &x : X) cin >> x;

    enumerate_cliques ec(N);
    while (M--) {
        int u, v;
        cin >> u >> v;
        ec.add_bi_edge(u, v);
    }
    mint ret = mint();

    auto op = [&](const std::vector<int> &clique) -> void {
        mint tmp = 1;
        for (int x : clique) tmp *= X.at(x);
        ret += tmp;
    };
    ec.run(op);

    cout << ret << endl;
}
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