sorry, no code cleaning here...

day 10/day_10_felix.cpp

+#include <bits/stdc++.h>
+using namespace std;
+const bool DEBUG = false;
+
+#define coord pair<int, int> 
+
+vector<vector<int>> trailMap;
+vector<coord> trailHeads;
+coord mapSize;
+const vector<coord> DIRS = {{-1, 0}, {1, 0}, {0, -1}, {0, 1}};
+
+void parseMap() {
+    DEBUG && cout << "Parsing map" << endl;
+    string line;
+    stringstream ss;
+    char c;
+    int row = 0;
+    int col = 0;
+    while (getline(cin, line)) {
+        DEBUG && cout << "Read line: " << line << endl;
+        ss = stringstream(line);
+        col = 0;
+        while (ss >> c) {
+            if (c == '0') trailHeads.push_back({row, col});
+            if (col == 0) trailMap.push_back({c - '0'});
+            else trailMap[row].push_back(c - '0');
+            col++;
+        }
+        row++;
+    }
+    mapSize = {row, col};
+}
+
+bool printMap() {
+    for (int i = 0; i < mapSize.first; i++) {
+        for (int j = 0; j < mapSize.second; j++) {
+            cout << trailMap[i][j] << " ";
+        }
+        cout << endl;
+    }
+    return false;
+}
+
+bool isInBounds(coord c) {
+    return c.first >= 0 && c.first < mapSize.first && c.second >= 0 && c.second < mapSize.second;
+}
+
+bool islegall(coord curr, coord next) {
+    return isInBounds(next) && trailMap[next.first][next.second] == trailMap[curr.first][curr.second] + 1;
+}
+
+int searchPart1(coord head) {
+    DEBUG && cout << "Searching from " << head.first << " " << head.second << endl;
+    vector<coord> toSearch = {head};
+    int n_nines = 0;
+    array<array<bool, 100>, 100> visited = {false};
+    while (!toSearch.empty()) {
+        coord curr = toSearch.back();
+        toSearch.pop_back();
+        if (visited[curr.first][curr.second]) continue;
+        visited[curr.first][curr.second] = true;
+        if (trailMap[curr.first][curr.second] == 9) {
+            n_nines++;
+            DEBUG && cout << "    Found a 9 at " << curr.first << " " << curr.second << endl;
+            continue;
+        }
+        for (coord dir : DIRS) {
+            coord next = {curr.first + dir.first, curr.second + dir.second};
+            if (islegall(curr,next)) toSearch.push_back(next);
+        }
+    }
+    return n_nines;
+}
+
+int searchPart2(coord head) {
+    DEBUG && cout << "Searching from " << head.first << " " << head.second << endl;
+    vector<coord> toSearch = {head};
+    int n_nines = 0;
+    //array<array<bool, 100>, 100> visited = {false};
+    while (!toSearch.empty()) {
+        coord curr = toSearch.back();
+        toSearch.pop_back();
+        //if (visited[curr.first][curr.second]) continue;
+        //visited[curr.first][curr.second] = true;
+        if (trailMap[curr.first][curr.second] == 9) {
+            n_nines++;
+            DEBUG && cout << "    Found a 9 at " << curr.first << " " << curr.second << endl;
+            continue;
+        }
+        for (coord dir : DIRS) {
+            coord next = {curr.first + dir.first, curr.second + dir.second};
+            if (islegall(curr,next)) toSearch.push_back(next);
+        }
+    }
+    return n_nines;
+}
+
+
+
+
+
+int main () {
+    parseMap();
+    DEBUG && printMap();
+    int p1 = 0;
+    int p2 = 0;
+    for (coord head : trailHeads) {
+        p1 += searchPart1(head);
+        p2 += searchPart2(head);
+    }
+    cout << "Part 1: " << p1 << endl;
+    cout << "Part 2: " << p2 << endl;
+    return 0;
+}
\ No newline at end of file

day 11/day_11_felix.cpp

+#include <bits/stdc++.h>
+using namespace std;
+const bool DEBUG = true;
+
+#define ll long long
+
+void add_to_map(map<ll, ll> &x, ll key, ll value) {
+    if (x.find(key) == x.end()) {
+        x[key] = value;
+    } else {
+        x[key] += value;
+    }
+}
+
+map<ll,ll> step(const map<ll,ll> &x0) {
+    map<ll, ll> x1;
+    for (auto [stone, count] : x0) {
+        if (count == 0) continue;
+        string numstring = to_string(stone);
+        if (stone == 0) add_to_map(x1, 1, count);
+        else if (numstring.size() % 2 == 0) {
+            ll left = stoi(numstring.substr(0, numstring.size() / 2));
+            ll right = stoi(numstring.substr(numstring.size() / 2, numstring.size() / 2));
+            add_to_map(x1, left, count);
+            add_to_map(x1, right, count);
+        } else {
+            if (stone >= LLONG_MAX / 2024) cout << "TOO LARGE! " << stone << endl;
+            add_to_map(x1, stone * 2024, count);
+        }
+    }
+    return x1;
+}
+
+map<ll,ll> read_input() {
+    map<ll, ll> state;
+    ll stone;
+    DEBUG && cout << "Reading input" << endl;
+    while (cin >> stone) {
+        DEBUG && cout << "   Stone: " << stone << endl;
+        add_to_map(state, stone, 1);
+    }
+    DEBUG && cout << "Input read" << endl;
+    return state;
+}
+
+ll sum_over(map<ll,ll> x) {
+    ll sum = 0;
+    for (auto [stone, count] : x) {
+        sum += count;
+    }
+    return sum;
+}
+
+int main () {
+    map<ll,ll> state = read_input();
+
+    for (int i = 0; i < 25; i++) {
+        state = step(state);
+    }
+    cout << "Part 1: " << sum_over(state) << endl;
+    for (int i = 0; i < 50; i++) {
+        state = step(state);
+        DEBUG && cout << "Step: " << i+25 << endl;
+        for (auto [stone, count] : state) {
+            DEBUG && cout << "   Stone: " << stone << " Count: " << count << endl;
+        }
+    }
+    cout << "Part 2: " << sum_over(state) << endl;
+
+    return 0;
+}
\ No newline at end of file

day 8/day_8_felix.cpp

+#include <bits/stdc++.h>
+using namespace std;
+const bool DEBUG = true;
+
+#define coord pair<int, int>
+map <char, vector<coord>> beacons;
+int nrows = 0;
+int ncols = 0;
+
+void parseInput() {
+    string line;
+    int row = 0;
+    while (getline(cin, line)) {
+        nrows++;
+        ncols = line.size();
+        for (int col = 0 ; col < line.size(); col++) {
+            if (line[col] != '.') {
+                beacons[line[col]].push_back({row, col});
+            }
+        }
+        row++;
+    }
+}
+
+bool isInBounds(coord a) {
+    return a.first >= 0 && a.first < nrows && a.second >= 0 && a.second < ncols;
+}
+
+pair<coord, coord> antinodePositions(coord a, coord b) {
+    coord newA = {a.first - (b.first - a.first), a.second - (b.second - a.second)};
+    coord newB = {b.first + (b.first - a.first), b.second + (b.second - a.second)};
+    return {newA, newB};
+}
+
+vector<coord> resonanceNodes(coord a, coord b) {
+    vector<coord> resNodes;
+    int dx = b.first - a.first;
+    int dy = b.second - a.second;
+    // Check modulus?
+    while (dx % 3 == 0 && dy % 3 == 0) {
+        dx = dx/3;
+        dy = dy/3;
+        cout << "Found modulus 3!" << endl;
+    }
+    while (dx % 2 == 0 && dy % 2 == 0) {
+        dx = dx/2;
+        dy = dy/2;
+        cout << "Found modulus 2!" << endl;
+    } 
+    while (dx % 5 == 0 && dy % 5 == 0) {
+        dx = dx/5;
+        dy = dy/5;
+        cout << "Found modulus 5!" << endl;
+    } 
+
+    coord newNode = a;
+    while (isInBounds(newNode)) {
+        resNodes.push_back(newNode);
+        newNode = {newNode.first - dx, newNode.second - dy};
+    }
+    newNode = {a.first + dx, a.second + dy};
+    while (isInBounds(newNode)) {
+        resNodes.push_back(newNode);
+        newNode = {newNode.first + dx, newNode.second + dy};
+    }
+    return resNodes;
+}
+
+int countAntinodes() {
+    int nantinodes = 0;
+    array<array<bool, 100>, 100> hasAntiNode = {false};
+
+    for (auto [key, freqbeacons] : beacons) {
+        for (int i = 0; i < freqbeacons.size(); i++) {
+            for (int j = i + 1; j < freqbeacons.size(); j++) {
+                auto [a, b] = antinodePositions(freqbeacons[i], freqbeacons[j]);
+                DEBUG && cout << "Beacons (" << freqbeacons[i].first << ", " << freqbeacons[i].second << ") and (" << freqbeacons[j].first << ", " << freqbeacons[j].second << ")" << endl;
+                if (isInBounds(a) && !hasAntiNode[a.first][a.second]) {
+                    nantinodes++;
+                    hasAntiNode[a.first][a.second] = true;
+                    DEBUG && cout << "Antinode at " << a.first << " " << a.second << endl;
+                }
+                if (isInBounds(b) && !hasAntiNode[b.first][b.second]) {
+                    nantinodes++;
+                    hasAntiNode[b.first][b.second] = true;
+                    DEBUG && cout << "Antinode at " << a.first << " " << a.second << endl;
+                }
+            }
+        }
+    }
+    return nantinodes;
+}
+
+bool printNodes(const array<array<bool, 100>, 100> &hasAntiNode) {
+    vector<string> grid;
+    for (int row = 0 ; row < nrows ; row++) {
+        grid.push_back("");
+        for (int col = 0; col < ncols; col++) {
+            if (hasAntiNode[row][col]) {
+                grid[row] += "#";
+            } else {
+                grid[row] += ".";
+            }
+        }
+    }
+    for (auto [key, freqbeacons] : beacons) {
+        for (auto beacon : freqbeacons) {
+            grid[beacon.first][beacon.second] = key;
+        }
+    }
+    for (auto row : grid) {
+        cout << row << endl;
+    }
+    return false;
+}
+
+int countFrequencyNodes() {
+    int nantinodes = 0;
+    array<array<bool, 100>, 100> hasAntiNode = {false};
+
+    for (auto [key, freqbeacons] : beacons) {
+        for (int i = 0; i < freqbeacons.size(); i++) {
+            for (int j = i + 1; j < freqbeacons.size(); j++) {
+                DEBUG && cout << key << "-beacons (" << freqbeacons[i].first << ", " << freqbeacons[i].second << ") and (" << freqbeacons[j].first << ", " << freqbeacons[j].second << ")" << endl;
+                DEBUG && cout << "Resonance nodes at ";
+                for (auto resNode : resonanceNodes(freqbeacons[i], freqbeacons[j])) {
+                    DEBUG && cout << "(" << resNode.first << ", " << resNode.second << "), ";
+                    if (!hasAntiNode[resNode.first][resNode.second]) {
+                        nantinodes++;
+                        hasAntiNode[resNode.first][resNode.second] = true;
+                    }
+                }
+                DEBUG && cout << endl;
+            }
+        }
+    }
+    DEBUG && printNodes(hasAntiNode);
+    return nantinodes;    
+}
+
+bool printBeacons() {
+    for (auto [key, freqbeacons] : beacons) {
+        cout << key << ": ";
+        for (auto beacon : freqbeacons) {
+            cout << "(" << beacon.first << ", " << beacon.second << ") ";
+        }
+        cout << endl;
+    }
+    return false;
+}
+
+int main () {
+    parseInput();
+    DEBUG && printBeacons();
+    cout << "Part 1: " << countAntinodes() << endl;
+    cout << "Part 2: " << countFrequencyNodes() << endl;
+    DEBUG && cout << "nrow: " << nrows << " ncols: " << ncols << endl;
+    return 0;
+}
\ No newline at end of file

day 9/day_9_felix.cpp

+#include <bits/stdc++.h>
+using namespace std;
+const bool DEBUG = false;
+
+deque<long long> input;
+deque<long long> fwdOriginal;
+
+void readInput() {
+    char c;
+    long long i = 0;
+    bool iseven = true;
+    while (cin >> c) {
+        input.push_back(c-'0');
+        if (iseven){
+            for (int j=0; j<c-'0'; j++) fwdOriginal.push_back(i);
+        } 
+        if (iseven) i++;
+        iseven = !iseven;
+    }
+}
+
+
+long long checkSum() {
+    deque<long long> fwd = fwdOriginal;
+    long long dig = 0;
+    long long hole = 0;
+
+    long long sum = 0;
+    long long pos = 0;
+    while (input.size() > 0) {
+        dig = input.front();
+        input.pop_front();
+        DEBUG && cout << "DIGIT " << dig << endl;
+        for (int i=0; i<dig; i++) {
+            long long val = fwd.front();
+            sum += pos * val;
+            DEBUG && cout << "Added " << val << " * " << pos << endl;
+            fwd.pop_front();
+            if (fwd.size() == 0) return sum;
+            pos++;
+        }
+
+        if (input.size() < 1) return sum;
+        hole = input.front();
+        input.pop_front();
+        DEBUG && cout << "HOLE" << endl;
+        for (int i=0; i<hole; i++) {
+            long long val = fwd.back();
+            sum += pos * val;
+            DEBUG && cout << "Added " << val << " * " << pos << endl;
+            fwd.pop_back();
+            if (fwd.size() == 0) return sum;
+            pos++;
+        }
+    }
+    return sum;
+}
+
+int main () {   
+    readInput();
+
+    long long part1 = checkSum();
+    cout << "Part 1: " << part1 << endl;
+    return 0;
+}
\ No newline at end of file

day 9/day_9_felix2.cpp

+#include <bits/stdc++.h>
+using namespace std;
+const bool DEBUG = true;
+
+#define ll long long
+
+vector <ll> fileid;
+vector <ll> filesize;
+vector <ll> filestart;
+
+vector <ll> holestart;
+vector <ll> holesize;
+
+void readInput() {
+    char c;
+    ll i = 0;
+    bool iseven = true;
+    ll pos = 0;
+    while (cin >> c) {
+        if (iseven) {
+            fileid.push_back(i);
+            filesize.push_back(c-'0');
+            filestart.push_back(pos);
+            i++;
+            pos += c-'0';
+        } else {
+            holestart.push_back(pos);
+            holesize.push_back(c-'0');
+            pos += c-'0';
+        }
+        iseven = !iseven;
+    }
+}
+
+
+void rearrange() {
+    DEBUG && cout << "Rearranging files" << endl;
+
+    for (int file = filesize.size()-1; file >= 0; file--) {
+        for (int hole = 0; hole < file; hole++) {
+            if (holesize[hole] >= filesize[file]) {
+                // insert file into hole
+                DEBUG && cout << "Inserting file " << fileid[file] << " into hole pos " << holestart[hole] << endl;
+                holesize[hole] -= filesize[file];
+                filestart[file] = holestart[hole];
+                holestart[hole] += filesize[file];
+                break;
+            }
+        }
+    }
+}
+
+ll fileValue(int file) {
+    ll val = 0;
+    for (ll i = 0; i < filesize[file]; i++) {
+        val += filestart[file] + i;
+    }
+    return val * fileid[file];
+}
+
+ll checkSum() {
+    ll sum = 0;
+    for (int file = 0; file < fileid.size(); file++) {
+        sum += fileValue(file);
+    }
+    return sum;
+}
+
+int main () {   
+    readInput();
+    rearrange();
+
+    long long part2 = checkSum();
+    cout << "Part 2: " << part2 << endl;
+    return 0;
+}
\ No newline at end of file