Algorithm to shuffle an Array randomly based on different weights

Question

I have a collection of elements that I want to shuffle randomly, but every element has a different priority or weight. So the element with bigger weight has to have more pro

Answer 1

Weighted Random Sampling (2005; Efraimidis, Spirakis) provides a very elegant algorithm for this. The implementation is super simple and runs in O(n log(n)):

def weigthed_shuffle(items, weights):
    order = sorted(range(len(items)), key=lambda i: -random.random() ** (1.0 / weights[i]))
    return [items[i] for i in order]