1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
|
// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
#pragma once
#include <algorithm>
#include <iterator>
#include <random>
template <class RandomIt, class DistIt, class URBG>
void weighted_shuffle(RandomIt first, RandomIt last,
DistIt weight_first, DistIt weight_last,
URBG &&g)
{
if (first == last) {
return;
} else if (std::accumulate(weight_first, weight_last, 0) == 0) {
return;
} else {
std::discrete_distribution d{weight_first, weight_last};
if (auto n = d(g); n > 0) {
std::iter_swap(first, std::next(first, n));
std::iter_swap(weight_first, std::next(weight_first, n));
}
weighted_shuffle(++first, last, ++weight_first, weight_last, std::move(g));
}
}
|
