cpp_src/utility/RandomLib.hpp

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• Last update: 2021-11-27 23:06:43+09:00
• Include: #include "cpp_src/utility/RandomLib.hpp"

Code

ll rand_int(ll l, ll r) {  //[l,r]
    static mt19937 gen(chrono::steady_clock::now().time_since_epoch().count());
    return uniform_int_distribution<ll>(l, r)(gen);
}

double rand_norm(double mean = 0.0, double sd = 1.0) {
    static mt19937 gen(chrono::steady_clock::now().time_since_epoch().count());
    return normal_distribution<>(mean, sd)(gen);
}

// x/y
bool rand_prob(ll x, ll y) { return rand_int(1, y) <= x; }

// Fisher–Yates
template <class T>
vector<T> random_perm(vector<T> vec) {
    vector<T> res;
    rep(i, vec.size()) {
        res.pb(vec[i]);
        int j = rand_int(0, i);
        swap(res[j], res[i]);
    }
    return res;
}

#line 1 "cpp_src/utility/RandomLib.hpp"
ll rand_int(ll l, ll r) {  //[l,r]
    static mt19937 gen(chrono::steady_clock::now().time_since_epoch().count());
    return uniform_int_distribution<ll>(l, r)(gen);
}

double rand_norm(double mean = 0.0, double sd = 1.0) {
    static mt19937 gen(chrono::steady_clock::now().time_since_epoch().count());
    return normal_distribution<>(mean, sd)(gen);
}

// x/y
bool rand_prob(ll x, ll y) { return rand_int(1, y) <= x; }

// Fisher–Yates
template <class T>
vector<T> random_perm(vector<T> vec) {
    vector<T> res;
    rep(i, vec.size()) {
        res.pb(vec[i]);
        int j = rand_int(0, i);
        swap(res[j], res[i]);
    }
    return res;
}

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