Random Number Generator
(src/util/RandomNumberGenerator.hpp)

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• Last update: 2023-12-18 21:46:16+09:00
• Include: #include "src/util/RandomNumberGenerator.hpp"

概要

一様乱数を生成する.

参照

Don’t use rand(): a guide to random number generators in C++ - Codeforces

Required by

• src/util/RandomUndirectedGraphGenarator.hpp

Code

#pragma once
#include <chrono>
#include <random>
#include <utility>
#include <vector>

struct RandomNumberGenerator {
    std::mt19937 mt;

    RandomNumberGenerator() : mt(std::chrono::steady_clock::now().time_since_epoch().count()) {}

    uint32_t operator()(uint32_t a, uint32_t b) {
        std::uniform_int_distribution<uint32_t> dist(a, b - 1);
        return dist(mt);
    }

    uint32_t operator()(uint32_t b) { return (*this)(0, b); }

    template <typename T> void shuffle(std::vector<T>& v) {
        for (int i = 0; i < int(v.size()); i++) std::swap(v[i], v[(*this)(0, i + 1)]);
    }
};

struct RandomNumberGenerator64 {
    std::mt19937_64 mt;

    RandomNumberGenerator64() : mt(std::chrono::steady_clock::now().time_since_epoch().count()) {}

    uint64_t operator()(uint64_t a, uint64_t b) {
        std::uniform_int_distribution<uint64_t> dist(a, b - 1);
        return dist(mt);
    }

    uint64_t operator()(uint64_t b) { return (*this)(0, b); }

    template <typename T> void shuffle(std::vector<T>& v) {
        for (int i = 0; i < int(v.size()); i++) std::swap(v[i], v[(*this)(0, i + 1)]);
    }
};

#line 2 "src/util/RandomNumberGenerator.hpp"
#include <chrono>
#include <random>
#include <utility>
#include <vector>

struct RandomNumberGenerator {
    std::mt19937 mt;

    RandomNumberGenerator() : mt(std::chrono::steady_clock::now().time_since_epoch().count()) {}

    uint32_t operator()(uint32_t a, uint32_t b) {
        std::uniform_int_distribution<uint32_t> dist(a, b - 1);
        return dist(mt);
    }

    uint32_t operator()(uint32_t b) { return (*this)(0, b); }

    template <typename T> void shuffle(std::vector<T>& v) {
        for (int i = 0; i < int(v.size()); i++) std::swap(v[i], v[(*this)(0, i + 1)]);
    }
};

struct RandomNumberGenerator64 {
    std::mt19937_64 mt;

    RandomNumberGenerator64() : mt(std::chrono::steady_clock::now().time_since_epoch().count()) {}

    uint64_t operator()(uint64_t a, uint64_t b) {
        std::uniform_int_distribution<uint64_t> dist(a, b - 1);
        return dist(mt);
    }

    uint64_t operator()(uint64_t b) { return (*this)(0, b); }

    template <typename T> void shuffle(std::vector<T>& v) {
        for (int i = 0; i < int(v.size()); i++) std::swap(v[i], v[(*this)(0, i + 1)]);
    }
};

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