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Update 20.cpp

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This commit is contained in:
Eric Mertens 2022-11-10 21:25:27 -08:00
parent 17728edb44
commit 3d665e5ebb
1 changed files with 5 additions and 5 deletions
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10
2019/20.cpp
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@ -118,11 +118,11 @@ auto FindDistances(Map const& map, Portals const& portals) {
Distances distances;
std::map<Coord, Name> names;
for (auto [k,v] : portals) {
for (auto const& [k,v] : portals) {
names[v] = k;
}
for (auto const [start_name, start_coord] : portals) {
for (auto const& [start_name, start_coord] : portals) {
distances[start_name] = FindDistancesFrom(map, names, distances, start_name, start_coord);
}
@ -132,11 +132,11 @@ auto FindDistances(Map const& map, Portals const& portals) {
auto SolveMaze(Distances const& distances, bool const recursive) -> std::int64_t
{
// Track current positions and current set of keys in easy to compare form
using Visited = std::pair<int, Name>;
using Visited = std::pair<std::int64_t, Name>;
std::set<Visited> seen;
// Priority queue returning lowest path cost states first.
using PqElt = std::tuple<std::int64_t, int, Name>;
using PqElt = std::tuple<std::int64_t, std::int64_t, Name>;
using PqCmp = decltype([](PqElt const& x, PqElt const& y) {
return std::get<0>(x) > std::get<0>(y); });
std::priority_queue<PqElt, std::vector<PqElt>, PqCmp> todo;
@ -144,7 +144,7 @@ auto SolveMaze(Distances const& distances, bool const recursive) -> std::int64_t
todo.emplace(0, 0, "-AA");
while(!todo.empty()) {
auto [steps, depth, name] = todo.top();
auto const [steps, depth, name] = todo.top();
todo.pop();
if (name == "-ZZ") { return steps; }
if (seen.emplace(depth, name).second) {