随机打乱一个数组

// shuffle algorithm example
#include <bits/stdc++.h>

using namespace std;

int main()
{
    //freopen("data.out", "w", stdout);

    vector<int> foo(5);

    for(int i=0;i<5;i++)
        foo[i] = i;

    unsigned seed = chrono::system_clock::now().time_since_epoch().count();

    shuffle(foo.begin(), foo.end(),default_random_engine(seed));

    cout << "shuffled elements:";

    for (int &x : foo)
        cout << ' ' << x;
    cout << '\n';

    return 0;
}

随机选择

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int i=uniform_int_distribution<int>(1,n)(rng),j=uniform_int_distribution<int>(1,n)(rng); //[1,n]
uniform_real_distribution<double>(1,10000)(rng)