bert/adventofcode
1
0
Fork 0
mirror of https://github.com/bertptrs/adventofcode.git synced 2025-12-25 21:00:31 +01:00
Code Issues Projects Releases Wiki Activity

Optimize day 18 a bit.

Browse Source
This commit is contained in:
Bert Peters
2019-12-23 23:36:33 +01:00
parent 2a75d1be4c
commit 8bbd9705a6
1 changed files with 14 additions and 20 deletions
Download Patch File Download Diff File Expand all files Collapse all files

34
2019/src/day18.cpp
View File

@@ -4,7 +4,7 @@
#include <unordered_map>
#include <unordered_set>
#include <bit>
#include <set>
#include <map>
#include "days.hpp"
#include "point.hpp"
@@ -108,7 +108,7 @@ void aoc2019::day18_part1(std::istream &input, std::ostream &output) {
auto implied_graph = compute_implied_graph(map);
std::priority_queue<std::pair<int, state_t>, std::vector<std::pair<int, state_t>>, std::greater<>> todo;
std::set<state_t> visited;
std::map<state_t, int> visited;
todo.emplace(0, std::make_pair(0, '@'));
auto target_size = std::count_if(implied_graph.cbegin(), implied_graph.cend(),
@@ -118,12 +118,10 @@ void aoc2019::day18_part1(std::istream &input, std::ostream &output) {
const auto[dist, state] = todo.top();
todo.pop();
if (visited.count(state)) {
if (visited[state] < dist) {
continue;
}
visited.insert(state);
auto[keys, pos] = state;
if (std::__popcount(keys) == target_size) {
@@ -145,11 +143,11 @@ void aoc2019::day18_part1(std::istream &input, std::ostream &output) {
}
state_t next_state = {next_keys, edge.first};
if (visited.count(next_state)) {
continue;
if (auto it = visited.find(next_state); it == visited.end() || it->second > next_dist) {
visited[next_state] = next_dist;
todo.emplace(next_dist, next_state);
}
todo.emplace(next_dist, next_state);
}
}
@@ -179,22 +177,21 @@ void aoc2019::day18_part2(std::istream &input, std::ostream &output) {
const auto implied_graph = compute_implied_graph(map);
std::priority_queue<std::pair<int, state_t>, std::vector<std::pair<int, state_t>>, std::greater<>> todo;
std::set<state_t> visited;
std::map<state_t, int> visited;
todo.emplace(0, state_t(0, {'@', '*', '^', '/'}));
auto target_size = std::count_if(implied_graph.cbegin(), implied_graph.cend(),
[](auto &x) { return std::islower(x.first); });
while (!todo.empty()) {
const auto[dist, state] = todo.top();
todo.pop();
if (visited.count(state)) {
if (visited[state] < dist) {
continue;
}
visited.insert(state);
auto[keys, pos] = state;
if (std::__popcount(keys) == target_size) {
@@ -204,9 +201,7 @@ void aoc2019::day18_part2(std::istream &input, std::ostream &output) {
for (int i = 0; i < 4; ++i) {
auto next_pos = pos;
char &subpos = next_pos[i];
for (const auto &edge : implied_graph.at(subpos)) {
for (const auto &edge : implied_graph.at(pos[i])) {
auto next_dist = dist + edge.second;
auto next_keys = keys;
if (std::islower(edge.first)) {
@@ -219,14 +214,13 @@ void aoc2019::day18_part2(std::istream &input, std::ostream &output) {
}
}
subpos = edge.first;
next_pos[i] = edge.first;
state_t next_state = {next_keys, next_pos};
if (visited.count(next_state)) {
continue;
if (auto it = visited.find(next_state); it == visited.end() || it->second > next_dist) {
visited[next_state] = next_dist;
todo.emplace(next_dist, next_state);
}
todo.emplace(next_dist, next_state);
}
}
}