C++ randomly sample k numbers from range 0:n-1 (n > k) without replacement

Question

I\'m working on porting a MATLAB simulation into C++. To do this, I am trying to replicate MATLAB\'s randsample() function. I haven\'t figured out an efficient way to do thi

Answer 1

Starting from C++17, there's a standard function for that: std::sample in library. It is guaranteed to have linear time complexity.

Sample _{(pun intended)} usage:

#include 
#include 
#include 
#include 
#include 

int main()
{
    std::vector population {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
    std::vector sample;
    std::sample(population.begin(), population.end(), 
                std::back_inserter(sample),
                5,
                std::mt19937{std::random_device{}()});
    for(int i: sample)
        std::cout << i << " "; //prints 5 randomly chosen values from population vector