2022-11-24 12:52:37 -08:00
|
|
|
#include <algorithm>
|
|
|
|
#include <cstdint>
|
|
|
|
#include <string>
|
|
|
|
#include <iostream>
|
|
|
|
#include <tuple>
|
|
|
|
#include <array>
|
|
|
|
#include <map>
|
|
|
|
|
|
|
|
#include <doctest.h>
|
|
|
|
|
|
|
|
#include <aocpp/Startup.hpp>
|
|
|
|
|
|
|
|
namespace {
|
|
|
|
|
|
|
|
template <std::size_t N>
|
|
|
|
using Banks = std::array<std::int64_t, N>;
|
|
|
|
|
|
|
|
auto Parse(std::istream & in) -> Banks<16> {
|
|
|
|
Banks<16> result;
|
|
|
|
for (auto & x : result) {
|
|
|
|
if (!(in >> x)) {
|
|
|
|
throw std::runtime_error{"bad input"};
|
|
|
|
}
|
|
|
|
}
|
2022-11-24 14:12:20 -08:00
|
|
|
|
2022-11-24 12:52:37 -08:00
|
|
|
return result;
|
|
|
|
}
|
|
|
|
|
|
|
|
template <std::size_t N>
|
|
|
|
auto Redistribute(Banks<N> & banks) {
|
|
|
|
auto it = std::max_element(banks.begin(), banks.end());
|
|
|
|
auto val = *it;
|
|
|
|
*it++ = 0;
|
|
|
|
for (; val > 0; val--) {
|
|
|
|
if (it == banks.end()) it = banks.begin();
|
|
|
|
(*it++)++;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
template <std::size_t N>
|
|
|
|
auto CycleSearch(Banks<N> & banks)
|
|
|
|
-> std::pair<std::size_t, std::size_t>
|
|
|
|
{
|
|
|
|
std::map<Banks<N>, std::size_t> seen {{banks, 0}};
|
|
|
|
std::size_t n = 0;
|
|
|
|
for(;;) {
|
|
|
|
Redistribute(banks);
|
|
|
|
n++;
|
|
|
|
auto [it, success] = seen.try_emplace(banks, n);
|
|
|
|
if (!success) {
|
|
|
|
return {n, n - it->second};
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
} // namespace
|
|
|
|
|
|
|
|
TEST_SUITE("2017-06 examples") {
|
|
|
|
TEST_CASE("example") {
|
|
|
|
Banks<4> banks {0, 2, 7, 0};
|
2022-11-24 14:12:20 -08:00
|
|
|
|
2022-11-24 12:52:37 -08:00
|
|
|
SUBCASE("single step") {
|
|
|
|
Redistribute(banks);
|
|
|
|
REQUIRE(banks == Banks<4>{2, 4, 1, 2});
|
|
|
|
Redistribute(banks);
|
|
|
|
REQUIRE(banks == Banks<4>{3, 1, 2, 3});
|
|
|
|
Redistribute(banks);
|
|
|
|
REQUIRE(banks == Banks<4>{0, 2, 3, 4});
|
|
|
|
Redistribute(banks);
|
|
|
|
REQUIRE(banks == Banks<4>{1, 3, 4, 1});
|
|
|
|
Redistribute(banks);
|
|
|
|
REQUIRE(banks == Banks<4>{2, 4, 1, 2});
|
|
|
|
}
|
|
|
|
|
|
|
|
SUBCASE("full example") {
|
|
|
|
auto [p1,p2] = CycleSearch(banks);
|
|
|
|
CHECK(p1 == 5);
|
|
|
|
CHECK(p2 == 4);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
auto main(int argc, char** argv) -> int {
|
|
|
|
auto input = Parse(*aocpp::Startup(argc, argv));
|
|
|
|
auto answer = CycleSearch(input);
|
|
|
|
std::cout << "Part 1: " << answer.first << std::endl;
|
|
|
|
std::cout << "Part 2: " << answer.second << std::endl;
|
2022-11-24 14:12:20 -08:00
|
|
|
}
|