AdventOfCode2024/src/HoofIt.cpp

114 lines
3.0 KiB
C++

// Solutions to the Advent Of Code 2024.
// Copyright (C) 2024-2025 Stefan Müller
//
// This program is free software: you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the Free Software
// Foundation, either version 3 of the License, or (at your option) any later
// version.
//
// This program is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
// FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along with
// this program. If not, see <http://www.gnu.org/licenses/>.
#include <aoc/HoofIt.hpp>
#include <memory>
#include <queue>
#include <vector>
#include <aoc/Grid.hpp>
#include <aoc/Point2.hpp>
const std::string HoofIt::getPuzzleName() const
{
return "Day 10: Hoof It";
}
const std::string HoofIt::getInputFileName() const
{
return "hoof_it.txt";
}
void HoofIt::finish()
{
std::queue<Point2> queue{};
Grid<std::vector<Point2>> trailEndsMap{ lines.size(), lines[0].size() };
Grid<int> trailScoreMap{ lines.size(), lines[0].size() };
for (int j = 0; j < lines.size(); j++)
{
for (int i = 0; i < lines[j].size(); i++)
{
trailScoreMap[j][i] = 0;
if (lines[j][i] == getTrailTopChar())
{
Point2 trailEnd{ i, j };
trailEndsMap[j][i].push_back(trailEnd);
trailScoreMap[j][i] = 1;
queue.push(trailEnd);
}
}
}
while (!queue.empty())
{
auto trail = queue.front();
queue.pop();
if (getCharAt(trail) != getTrailheadChar())
{
for (auto direction : Point2::cardinalDirections)
{
Point2 p{ trail + direction };
if (isInBounds(p) && getCharAt(p) + 1 == getCharAt(trail))
{
if (trailEndsMap[p.y][p.x].empty())
{
queue.push(p);
}
addUnique(trailEndsMap.cell(trail), trailEndsMap.cell(p));
trailScoreMap.cell(p) += trailScoreMap.cell(trail);
}
}
}
else
{
part1 += trailEndsMap.cell(trail).size();
part2 += trailScoreMap.cell(trail);
}
}
}
constexpr char HoofIt::getTrailheadChar()
{
return '0';
}
constexpr char HoofIt::getTrailTopChar()
{
return '9';
}
void HoofIt::addUnique(const std::vector<Point2>& source, std::vector<Point2>& destination)
{
for (auto end : source)
{
auto isUnique{ true };
size_t i{ 0 };
while (isUnique && i < destination.size())
{
if (end == destination[i])
{
isUnique = false;
}
i++;
}
if (isUnique)
{
destination.push_back(end);
}
}
}