Random Number Generator
(utility/random_number_generator.hpp)

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• Last update: 2024-08-06 16:15:06+09:00
• Include: #include "utility/random_number_generator.hpp"

説明

整数の乱数生成機。

set_seed(seed)

シードを指定する。

get(a, b)

$[a, b)$ の範囲から一様乱数を生成する。

Required by

• Maximum Matching Size (graph/maximum_matching_size.hpp)
• Black Box Linear Algebra (matrix/black_box_linear_algebra.hpp)
• Rolling Hash Monoid (monoid/rolling_hash_monoid.hpp)
• Rolling Hash (string/rolling_hash.hpp)
• Wildcard Pattern Matching (string/wildcard_pattern_matching.hpp)
• Subtree Hash (tree/subtree_hash.hpp)
• Tree Hash (tree/tree_hash.hpp)
• Hash structure (utility/hash.hpp)

Verified with

• test/aoj/aoj_2444.test.cpp
• test/aoj/aoj_2821.test.cpp
• test/convolution/Convolution_2D.test.cpp
• test/data_structure/Range_Parallel_DSU_Stress_test.test.cpp
• test/math/Negative_Binomial_Coefficient.test.cpp
• test/math/Sum_of_Powers_Iota.test.cpp
• test/matrix/Determinant_of_Sparse_Matrix.test.cpp
• test/string/Wildcard_Pattern_Matching.test.cpp
• test/tree/Rooted_Tree_Isomorphism_Classification.test.cpp
• test/yuki/yuki_1112.test.cpp

Code

#pragma once

#include <algorithm>

#include <cstdint>

#include <numeric>

#include <random>

#include <vector>


namespace ebi {

struct random_number_generator {
    random_number_generator(int seed = -1) {
        if (seed < 0) seed = rnd();
        mt.seed(seed);
    }

    void set_seed(int seed) {
        mt.seed(seed);
    }

    template <class T> T get(T a, T b) {
        std::uniform_int_distribution<T> dist(a, b - 1);
        return dist(mt);
    }

    std::vector<int> get_permutation(int n) {
        std::vector<int> p(n);
        std::iota(p.begin(), p.end(), 0);
        std::shuffle(p.begin(), p.end(), mt);
        return p;
    }

  private:
    std::mt19937_64 mt;
    std::random_device rnd;
};

}  // namespace ebi

#line 2 "utility/random_number_generator.hpp"

#include <algorithm>

#include <cstdint>

#include <numeric>

#include <random>

#include <vector>


namespace ebi {

struct random_number_generator {
    random_number_generator(int seed = -1) {
        if (seed < 0) seed = rnd();
        mt.seed(seed);
    }

    void set_seed(int seed) {
        mt.seed(seed);
    }

    template <class T> T get(T a, T b) {
        std::uniform_int_distribution<T> dist(a, b - 1);
        return dist(mt);
    }

    std::vector<int> get_permutation(int n) {
        std::vector<int> p(n);
        std::iota(p.begin(), p.end(), 0);
        std::shuffle(p.begin(), p.end(), mt);
        return p;
    }

  private:
    std::mt19937_64 mt;
    std::random_device rnd;
};

}  // namespace ebi

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