117 lines
2.9 KiB
C++
117 lines
2.9 KiB
C++
#include <array>
|
|
#include <functional>
|
|
#include <iostream>
|
|
#include <string>
|
|
#include <vector>
|
|
|
|
#include "graph-utils.h"
|
|
|
|
using Int = std::int64_t;
|
|
|
|
struct Pos
|
|
{
|
|
Pos() noexcept = default;
|
|
Pos(Int x, Int y) noexcept : x_(x), y_(y) {}
|
|
Pos(Pos const&) noexcept = default;
|
|
auto operator=(Pos const&) noexcept -> Pos& = default;
|
|
Pos(Pos&&) noexcept = default;
|
|
auto operator=(Pos&&) noexcept -> Pos& = default;
|
|
~Pos() noexcept = default;
|
|
|
|
[[nodiscard]] auto x() const { return x_; }
|
|
[[nodiscard]] auto y() const { return y_; }
|
|
|
|
private:
|
|
Int x_{0};
|
|
Int y_{0};
|
|
};
|
|
|
|
auto operator+(Pos const& x, Pos const& y) noexcept -> Pos
|
|
{
|
|
return Pos{x.x() + y.x(), x.y() + y.y()};
|
|
}
|
|
|
|
auto operator<(Pos const& l, Pos const& r) noexcept -> bool
|
|
{
|
|
return l.y() < r.y() || (l.y() == r.y() && l.x() < r.x());
|
|
}
|
|
|
|
auto operator==(Pos const& l, Pos const& r) noexcept -> bool
|
|
{
|
|
return l.x() == r.x() && l.y() == r.y();
|
|
}
|
|
|
|
using Height = char;
|
|
|
|
struct Map
|
|
{
|
|
explicit Map(std::istream& is)
|
|
{
|
|
std::string line;
|
|
while (std::getline(is, line)) {
|
|
auto s = line.find('S');
|
|
if (s != std::string::npos) {
|
|
start_ = Pos{static_cast<Int>(s), static_cast<Int>(rows_.size())};
|
|
line[s] = 'a';
|
|
}
|
|
auto e = line.find('E');
|
|
if (e != std::string::npos) {
|
|
end_ = Pos{static_cast<Int>(e), static_cast<Int>(rows_.size())};
|
|
line[e] = 'z';
|
|
}
|
|
rows_.push_back(line);
|
|
}
|
|
}
|
|
[[nodiscard]] auto start() const -> Pos { return start_; }
|
|
[[nodiscard]] auto end() const -> Pos { return end_; }
|
|
[[nodiscard]] auto width() const -> Int { return static_cast<Int>(rows_[0].length()); }
|
|
[[nodiscard]] auto depth() const -> Int { return static_cast<Int>(rows_.size()); }
|
|
[[nodiscard]] auto height(Pos const& p) const -> Height
|
|
{
|
|
return rows_[p.y()][p.x()];
|
|
}
|
|
|
|
private:
|
|
std::vector<std::string> rows_;
|
|
Pos start_{0, 0};
|
|
Pos end_{0, 0};
|
|
};
|
|
|
|
struct StateTranstitionManager
|
|
{
|
|
explicit StateTranstitionManager(Map map) : map_(std::move(map)) {}
|
|
|
|
Map map_;
|
|
|
|
[[nodiscard]] auto is_finished(Pos const& pos) const -> bool { return map_.height(pos) == 'a'; }
|
|
|
|
template<typename Inserter>
|
|
void generate_children(Pos const& current, Inserter inserter) const
|
|
{
|
|
std::array<Pos, 4> const moves{Pos{0, 1}, Pos{0, -1}, Pos{1, 0}, Pos{-1, 0}};
|
|
for (auto const& move : moves) {
|
|
auto pos{current + move};
|
|
// Check in bounds
|
|
if (pos.x() < 0 || pos.x() > map_.width() || pos.y() < 0 || pos.y() > map_.depth()) {
|
|
continue;
|
|
}
|
|
// check height hasn't changed too far
|
|
if (map_.height(pos) < map_.height(current) - 1) {
|
|
continue;
|
|
}
|
|
inserter(pos, 1);
|
|
}
|
|
}
|
|
};
|
|
|
|
auto main() -> int
|
|
{
|
|
Map const map(std::cin);
|
|
Pos const initial_state{map.end()};
|
|
|
|
auto [finished_state, finished_cost] =
|
|
dijkstra(initial_state, Int{0}, StateTranstitionManager{map});
|
|
std::cout << "Done with cost " << finished_cost << '\n';
|
|
return 0;
|
|
}
|