Спринт 8. Move-итераторы. Задание 1.

#include <cassert>
#include <iostream>
#include <numeric>
#include <vector>
#include <list>
#include <utility>

using namespace std;

template <typename RandomIt>
void MakeJosephusPermutation(RandomIt first, RandomIt last, uint32_t step_size) {
    list<typename RandomIt::value_type> pool(make_move_iterator(first), make_move_iterator(last));
    size_t cur_pos = 0;
    while (!pool.empty()) {
        auto iter = pool.begin();
        advance(iter, cur_pos);
        *(first++) = move(*iter);
        iter = pool.erase(iter);
        if (pool.empty()) {
            break;
        }
        cur_pos = (cur_pos+step_size-1)% pool.size();
    }
}

vector<int> MakeTestVector() {
    vector<int> numbers(10);
    iota(begin(numbers), end(numbers), 0);
    return numbers;
}

void TestIntVector() {
    const vector<int> numbers = MakeTestVector();
    {
        vector<int> numbers_copy = numbers;
        MakeJosephusPermutation(begin(numbers_copy), end(numbers_copy), 1);
        assert(numbers_copy == numbers);
    }
    {
        vector<int> numbers_copy = numbers;
        MakeJosephusPermutation(begin(numbers_copy), end(numbers_copy), 3);
        assert(numbers_copy == vector<int>({0, 3, 6, 9, 4, 8, 5, 2, 7, 1}));
    }
}

struct NoncopyableInt {
    int value;

    NoncopyableInt(const NoncopyableInt&) = delete;
    NoncopyableInt& operator=(const NoncopyableInt&) = delete;

    NoncopyableInt(NoncopyableInt&&) = default;
    NoncopyableInt& operator=(NoncopyableInt&&) = default;
};

bool operator==(const NoncopyableInt& lhs, const NoncopyableInt& rhs) {
    return lhs.value == rhs.value;
}

ostream& operator<<(ostream& os, const NoncopyableInt& v) {
    return os << v.value;
}

void TestAvoidsCopying() {
    vector<NoncopyableInt> numbers;
    numbers.push_back({1});
    numbers.push_back({2});
    numbers.push_back({3});
    numbers.push_back({4});
    numbers.push_back({5});

    MakeJosephusPermutation(begin(numbers), end(numbers), 2);

    vector<NoncopyableInt> expected;
    expected.push_back({1});
    expected.push_back({3});
    expected.push_back({5});
    expected.push_back({4});
    expected.push_back({2});

    assert(numbers == expected);
}

int main() {
    TestIntVector();
    TestAvoidsCopying();
}