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Solve 2024 day 8 part 2

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SebastianStork 2025-01-02 22:58:46 +01:00
parent ffc564f048
commit 3c40f13cfc
1 changed files with 67 additions and 15 deletions
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80
2024/day-08/main.cpp
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@ -1,6 +1,7 @@
#include <iostream>
#include <map>
#include <set>
#include <utility>
#include <vector>
using namespace std;
@ -23,27 +24,31 @@ void readInput(vector<string> &antennaMap, map<char, set<pair<int, int>>> &anten
}
}
bool isInBounds(pair<int, int> location, const vector<string> &map)
pair<int, int> getDirectionVector(const pair<int, int> &antenna1, const pair<int, int> &antenna2)
{
return (location.first >= 0 && location.first < map.size())
&& (location.second >= 0 && location.second < map[0].size());
return {antenna2.first - antenna1.first, antenna2.second - antenna1.second};
}
vector<pair<int, int>> getAntinodes(pair<int, int> antenna1,
pair<int, int> antenna2,
bool isInBounds(const pair<int, int> &location, const vector<string> &map)
{
return (location.first >= 0 && cmp_less(location.first, map.size()))
&& (location.second >= 0 && cmp_less(location.second, map[0].size()));
}
vector<pair<int, int>> getAntinodes(const pair<int, int> &antenna1,
const pair<int, int> &antenna2,
const vector<string> &antennaMap)
{
if (antenna1 == antenna2) {
return {};
}
pair<int, int> directionVector = {antenna2.first - antenna1.first,
antenna2.second - antenna1.second};
const pair<int, int> directionVector = getDirectionVector(antenna1, antenna2);
pair<int, int> antinode1 = {antenna2.first + directionVector.first,
antenna2.second + directionVector.second};
pair<int, int> antinode2 = {antenna1.first - directionVector.first,
const pair<int, int> antinode1 = {antenna1.first - directionVector.first,
antenna1.second - directionVector.second};
const pair<int, int> antinode2 = {antenna2.first + directionVector.first,
antenna2.second + directionVector.second};
vector<pair<int, int>> antinodes;
if (isInBounds(antinode1, antennaMap)) {
@ -55,6 +60,34 @@ vector<pair<int, int>> getAntinodes(pair<int, int> antenna1,
return antinodes;
}
vector<pair<int, int>> getResonantHarmonicsAntinodes(const pair<int, int> &antenna1,
const pair<int, int> &antenna2,
const vector<string> &antennaMap)
{
if (antenna1 == antenna2) {
return {};
}
const pair<int, int> directionVector = getDirectionVector(antenna1, antenna2);
vector<pair<int, int>> antinodes;
pair<int, int> antinode1 = antenna1;
do {
antinodes.push_back(antinode1);
antinode1.first -= directionVector.first;
antinode1.second -= directionVector.second;
} while (isInBounds(antinode1, antennaMap));
pair<int, int> antinode2 = antenna2;
do {
antinodes.push_back(antinode2);
antinode2.first += directionVector.first;
antinode2.second += directionVector.second;
} while (isInBounds(antinode2, antennaMap));
return antinodes;
}
int main()
{
vector<string> antennaMap;
@ -62,18 +95,37 @@ int main()
readInput(antennaMap, antennas);
set<pair<int, int>> uniqueAntinodes;
set<pair<int, int>> uniqueResonantHarmonicsAntinodes;
set<pair<pair<int, int>, pair<int, int>>> consideredAntennaCombinations;
for (auto antennasWithSameFrequency : antennas) {
for (auto antenna1 : antennasWithSameFrequency.second) {
for (auto antenna2 : antennasWithSameFrequency.second) {
vector<pair<int, int>> foundAntinodes = getAntinodes(antenna1, antenna2, antennaMap);
for (const auto &antennasWithSameFrequency : antennas) {
for (const auto &antenna1 : antennasWithSameFrequency.second) {
for (const auto &antenna2 : antennasWithSameFrequency.second) {
const auto orderedPair = make_pair(min(antenna1, antenna2), max(antenna1, antenna2));
if (consideredAntennaCombinations.contains(orderedPair)) {
continue;
}
consideredAntennaCombinations.insert(orderedPair);
const vector<pair<int, int>> foundAntinodes = getAntinodes(antenna1,
antenna2,
antennaMap);
for (pair<int, int> antinode : foundAntinodes) {
uniqueAntinodes.insert(antinode);
}
const vector<pair<int, int>> foundResonantHarmonicsAntinodes
= getResonantHarmonicsAntinodes(antenna1, antenna2, antennaMap);
for (pair<int, int> antinode : foundResonantHarmonicsAntinodes) {
uniqueResonantHarmonicsAntinodes.insert(antinode);
}
}
}
}
// Part one
cout << "Number of unique antinodes: " << uniqueAntinodes.size() << endl;
// Part two
cout << "Number of unique antinodes when taking resonant harmonics into account: "
<< uniqueResonantHarmonicsAntinodes.size() << endl;
}