Shuffles

Shuffles.cpp

#include <iostream>
#include <vector>

int getAt(long i, int n, int m) {
    long long tmpI = i;
    for (int tmpN = n; tmpN > 0; tmpN--) {
        long long half = m * /*pow(2, tmpN - 1)*/ (1LL << (tmpN - 1));
        long long quarter = (half + 1) / 2;
        long long adjustedI = tmpI % half;
        if (adjustedI < quarter) {
            tmpI = adjustedI * 2;
        }
        else {
            tmpI = ((adjustedI - quarter) * 2 + 1);
        }
    }
    return static_cast<int>(tmpI);
}

std::vector<int> solve(int n, int m, long a, long b) {
    std::vector<int> output(b - a);
    for (long i = a; i < b; i++) {
        output[static_cast<std::size_t>(i - a)] = getAt(i, n, m);
    }
    return output;
}

int main()
{
    auto solution = solve(58, 57, 0, 104);
    for (auto s : solution) {
        std::cout << s << " ";
    }
}