Move c++ solutions into separate directory

2026-01-21 16:51:34 +01:00 · 2025-01-06 17:12:41 +01:00 · 2025-01-06 17:12:41 +01:00 · 4adbe68617
commit 4adbe68617
parent 3c40f13cfc
28 changed files with 1 additions and 1 deletions
--- a/2024/cpp/day-08/main.cpp
+++ b/2024/cpp/day-08/main.cpp
@ -0,0 +1,131 @@
+#include <iostream>
+#include <map>
+#include <set>
+#include <utility>
+#include <vector>
+
+using namespace std;
+
+void readInput(vector<string> &antennaMap, map<char, set<pair<int, int>>> &antennas)
+{
+    string line;
+    for (size_t row = 0; getline(cin, line); row++) {
+        for (size_t col = 0; col < line.size(); col++) {
+            char frequency = line[col];
+            if (frequency != '.') {
+                if (antennas.count(frequency)) {
+                    antennas.at(frequency).insert({row, col});
+                } else {
+                    antennas.insert({frequency, {{row, col}}});
+                }
+            }
+        }
+        antennaMap.push_back(line);
+    }
+}
+
+pair<int, int> getDirectionVector(const pair<int, int> &antenna1, const pair<int, int> &antenna2)
+{
+    return {antenna2.first - antenna1.first, antenna2.second - antenna1.second};
+}
+
+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 {};
+    }
+
+    const pair<int, int> directionVector = getDirectionVector(antenna1, antenna2);
+
+    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)) {
+        antinodes.push_back(antinode1);
+    }
+    if (isInBounds(antinode2, antennaMap)) {
+        antinodes.push_back(antinode2);
+    }
+    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;
+    map<char, set<pair<int, int>>> antennas;
+    readInput(antennaMap, antennas);
+
+    set<pair<int, int>> uniqueAntinodes;
+    set<pair<int, int>> uniqueResonantHarmonicsAntinodes;
+    set<pair<pair<int, int>, pair<int, int>>> consideredAntennaCombinations;
+
+    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;
+}