Ranked Subset Transform (Zeta / Mobius)
(set_function/ranked_subset_transform.hpp)

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• Last update: 2023-10-31 00:17:11+09:00
• Include: #include "set_function/ranked_subset_transform.hpp"

説明

重み付きゼータ変換 / メビウス変換を行う。 $O(N^2\log N)$

Required by

• Subset Convolution (convolution/subset_convolution.hpp)
• $f(a)$ (Set Power Series, f is EGF) (set_function/egf_composite_sps.hpp)
• $\exp {a}$ (Set Power Series) (set_function/exp_of_sps.hpp)
• $f(a)$ (Set Power Series, f is FPS) (set_function/poly_composite_sps.hpp)

Verified with

• test/convolution/Subset_Convolution.test.cpp
• test/set_function/Exp_of_Set_Power_Series.test.cpp
• test/set_function/Polynomial_Composite_Set_Power_Series.test.cpp

Code

#pragma once

#include <array>
#include <bit>
#include <cassert>
#include <vector>

namespace ebi {

template <class T, int LIM = 20>
std::vector<std::array<T, LIM + 1>> ranked_zeta(const std::vector<T> &f) {
    int n = std::bit_width(f.size()) - 1;
    assert(n <= LIM);
    assert((int)f.size() == (1 << n));
    std::vector<std::array<T, LIM + 1>> rf(1 << n);
    for (int s = 0; s < (1 << n); s++)
        rf[s][std::popcount((unsigned int)(s))] = f[s];
    for (int i = 0; i < n; i++) {
        int w = 1 << i;
        for (int p = 0; p < (1 << n); p += 2 * w) {
            for (int s = p; s < p + w; s++) {
                int t = s | (1 << i);
                for (int d = 0; d <= n; d++) rf[t][d] += rf[s][d];
            }
        }
    }
    return rf;
}

template <class T, int LIM = 20>
std::vector<T> ranked_mobius(std::vector<std::array<T, LIM + 1>> rf) {
    int n = std::bit_width(rf.size()) - 1;
    assert((int)rf.size() == (1 << n));
    for (int i = 0; i < n; i++) {
        int w = 1 << i;
        for (int p = 0; p < (1 << n); p += 2 * w) {
            for (int s = p; s < p + w; s++) {
                int t = s | (1 << i);
                for (int d = 0; d <= n; d++) rf[t][d] -= rf[s][d];
            }
        }
    }
    std::vector<T> f(1 << n);
    for (int s = 0; s < (1 << n); s++) {
        f[s] = rf[s][std::popcount((unsigned int)(s))];
    }
    return f;
}

}  // namespace ebi

#line 2 "set_function/ranked_subset_transform.hpp"

#include <array>
#include <bit>
#include <cassert>
#include <vector>

namespace ebi {

template <class T, int LIM = 20>
std::vector<std::array<T, LIM + 1>> ranked_zeta(const std::vector<T> &f) {
    int n = std::bit_width(f.size()) - 1;
    assert(n <= LIM);
    assert((int)f.size() == (1 << n));
    std::vector<std::array<T, LIM + 1>> rf(1 << n);
    for (int s = 0; s < (1 << n); s++)
        rf[s][std::popcount((unsigned int)(s))] = f[s];
    for (int i = 0; i < n; i++) {
        int w = 1 << i;
        for (int p = 0; p < (1 << n); p += 2 * w) {
            for (int s = p; s < p + w; s++) {
                int t = s | (1 << i);
                for (int d = 0; d <= n; d++) rf[t][d] += rf[s][d];
            }
        }
    }
    return rf;
}

template <class T, int LIM = 20>
std::vector<T> ranked_mobius(std::vector<std::array<T, LIM + 1>> rf) {
    int n = std::bit_width(rf.size()) - 1;
    assert((int)rf.size() == (1 << n));
    for (int i = 0; i < n; i++) {
        int w = 1 << i;
        for (int p = 0; p < (1 << n); p += 2 * w) {
            for (int s = p; s < p + w; s++) {
                int t = s | (1 << i);
                for (int d = 0; d <= n; d++) rf[t][d] -= rf[s][d];
            }
        }
    }
    std::vector<T> f(1 << n);
    for (int s = 0; s < (1 << n); s++) {
        f[s] = rf[s][std::popcount((unsigned int)(s))];
    }
    return f;
}

}  // namespace ebi

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