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#include <iostream>
#include <vector>
using namespace std;
namespace {
void
part1(size_t steps, size_t iterations)
{
vector<size_t> buffer{ 0 };
size_t pos = 0;
for ( size_t i = 1; i <= iterations; ++i ) {
pos = (pos + steps) % i + 1;
buffer.insert(buffer.begin() + static_cast<vector<size_t>::difference_type>(pos), i);
}
cout << "Part1: " << buffer[(pos + 1) % buffer.size()] << '\n';
}
void
part2(size_t steps, size_t iterations)
{
size_t pos = 0;
size_t value = 0;
for ( size_t i = 1; i <= iterations; ++i ) {
pos = (pos + steps) % i;
if ( pos == 0 ) {
value = i;
}
pos = (pos + 1) % (i + 1);
}
cout << "Part2: " << value << '\n';
}
} // namespace
int
main()
{
const auto input = 371;
part1(input, 2017);
part2(input, 50'000'000);
}
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