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Add 2017 Day 24 puzzles

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Matthew Gretton-Dann
2021-12-22 15:57:06 +00:00
parent d1e6f5b086
commit e06e78ce3c
2 changed files with 167 additions and 0 deletions
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83
2017/puzzle-24-01.cc Normal file
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#include <iostream>
#include <numeric>
#include <regex>
#include <string>
#include <vector>
using UInt = unsigned long;
using Chain = std::pair<UInt, UInt>;
struct State
{
void add(Chain const& chain) { chains_.push_back({chain, false}); }
template<typename Inserter>
void next_states(Inserter inserter) const
{
State next(*this);
for (auto& chain : next.chains_) {
if (chain.second) {
continue;
}
if (chain.first.first == tail_end_) {
next.tail_end_ = chain.first.second;
chain.second = true;
*inserter++ = next;
}
if (chain.first.second == tail_end_) {
next.tail_end_ = chain.first.first;
chain.second = true;
*inserter++ = next;
}
chain.second = false;
}
}
[[nodiscard]] auto strength() const noexcept -> UInt
{
return std::accumulate(chains_.begin(), chains_.end(), UInt{0}, [](UInt a, auto const& c) {
if (c.second) {
return a + c.first.first + c.first.second;
}
else {
return a;
}
});
}
private:
UInt tail_end_{0};
std::vector<std::pair<Chain, bool>> chains_;
};
auto main() -> int
{
std::regex re{"(\\d+)/(\\d+)"};
std::string line;
State initial_state;
while (std::getline(std::cin, line) && !line.empty()) {
std::smatch m;
if (!std::regex_search(line, m, re)) {
std::cerr << "Unable to interpret: " << line << '\n';
return 1;
}
initial_state.add({std::stoul(m.str(1)), std::stoul(m.str(2))});
}
auto strength{initial_state.strength()};
std::vector<State> states;
states.push_back(initial_state);
while (!states.empty()) {
std::vector<State> next_states;
auto inserter{std::back_inserter(next_states)};
for (auto const& state : states) {
strength = std::max(strength, state.strength());
state.next_states(inserter);
}
std::swap(states, next_states);
}
std::cout << "Max strength: " << strength << '\n';
return 0;
}

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2017/puzzle-24-02.cc Normal file
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#include <iostream>
#include <numeric>
#include <regex>
#include <string>
#include <vector>
using UInt = unsigned long;
using Chain = std::pair<UInt, UInt>;
struct State
{
void add(Chain const& chain) { chains_.push_back({chain, false}); }
template<typename Inserter>
void next_states(Inserter inserter) const
{
State next(*this);
for (auto& chain : next.chains_) {
if (chain.second) {
continue;
}
if (chain.first.first == tail_end_) {
next.tail_end_ = chain.first.second;
chain.second = true;
*inserter++ = next;
}
if (chain.first.second == tail_end_) {
next.tail_end_ = chain.first.first;
chain.second = true;
*inserter++ = next;
}
chain.second = false;
}
}
[[nodiscard]] auto strength() const noexcept -> UInt
{
return std::accumulate(chains_.begin(), chains_.end(), UInt{0}, [](UInt a, auto const& c) {
if (c.second) {
return a + c.first.first + c.first.second;
}
else {
return a;
}
});
}
private:
UInt tail_end_{0};
std::vector<std::pair<Chain, bool>> chains_;
};
auto main() -> int
{
std::regex re{"(\\d+)/(\\d+)"};
std::string line;
State initial_state;
while (std::getline(std::cin, line) && !line.empty()) {
std::smatch m;
if (!std::regex_search(line, m, re)) {
std::cerr << "Unable to interpret: " << line << '\n';
return 1;
}
initial_state.add({std::stoul(m.str(1)), std::stoul(m.str(2))});
}
auto strength{initial_state.strength()};
std::vector<State> states;
states.push_back(initial_state);
while (!states.empty()) {
std::vector<State> next_states;
strength = 0;
auto inserter{std::back_inserter(next_states)};
for (auto const& state : states) {
strength = std::max(strength, state.strength());
state.next_states(inserter);
}
std::swap(states, next_states);
}
std::cout << "Max strength: " << strength << '\n';
return 0;
}