Day 14

.gitignore

@@ -1 +1,3 @@
 .vscode
+*/*
+!**/*.cpp

Day 11/part1.cpp

@@ -0,0 +1,112 @@
+#include <iostream>
+#include <string>
+#include <algorithm>
+
+using namespace std;
+
+constexpr int grid_size{10};
+int grid[grid_size][grid_size] = {0};
+
+void output_grid();
+
+std::ostream& bold_on(std::ostream& os);
+std::ostream& bold_off(std::ostream& os);
+
+int main(int argc, char* argv[])
+{
+    string line = "";
+
+    for (int y = 0; y < grid_size; y++)
+    {
+        getline(cin, line);
+        for (int x = 0; x < grid_size; x++)
+        {
+            grid[x][y] = (int)(line[x]-'0');
+        }
+    }
+
+    int total_flashes = 0;
+    for (int t = 0; t < 100; t++)
+    {
+        //Step 1, increment
+        for (int y = 0; y < grid_size; y++)
+        {
+            for (int x = 0; x < grid_size; x++)
+            {
+                ++grid[x][y];
+            }
+        }
+
+        //Step 2, flash
+        bool flashed[grid_size][grid_size] = {false};
+        bool flash_occurred = false;
+        do
+        {
+            flash_occurred = false;
+            for (int y = 0; y < grid_size; y++)
+            {
+                for (int x = 0; x < grid_size; x++)
+                {
+                    if (!flashed[x][y] && grid[x][y] > 9)
+                    {
+                        flashed[x][y] = true;
+                        flash_occurred = true;
+                        ++total_flashes;
+
+                        for(int fy = max(0,y-1); fy < min(grid_size, y+2); fy++)
+                        {
+                            for(int fx = max(0,x-1); fx < min(grid_size,x+2); fx++)
+                            {
+                                grid[fx][fy]++;
+                            }
+                        }
+                    }
+                }
+            }
+        } while (flash_occurred);
+
+        //Step 3, flashed are cleared
+        for (int y = 0; y < grid_size; y++)
+        {
+            for (int x = 0; x < grid_size; x++)
+            {
+                if (flashed[x][y])
+                {
+                    grid[x][y] = 0;
+                }
+            }
+        }
+    }
+
+    cout << total_flashes << endl;
+}
+
+void output_grid()
+{
+    for (int y = 0; y < grid_size; y++)
+    {
+        for (int x = 0; x < grid_size; x++)
+        {
+            if (0 == grid[x][y])
+            {
+                cout << bold_on << grid[x][y] << bold_off;
+            }
+            else
+            {
+                cout << grid[x][y];
+            }
+        }
+        cout << endl;
+    }
+    cout << endl;
+}
+
+std::ostream& bold_on(std::ostream& os)
+{
+    return os << "\e[1m";
+}
+
+std::ostream& bold_off(std::ostream& os)
+{
+    return os << "\e[0m";
+}

Day 11/part2.cpp

@@ -0,0 +1,119 @@
+#include <iostream>
+#include <string>
+#include <algorithm>
+
+using namespace std;
+
+constexpr int grid_size{10};
+int grid[grid_size][grid_size] = {0};
+
+void output_grid();
+
+std::ostream& bold_on(std::ostream& os);
+std::ostream& bold_off(std::ostream& os);
+
+int main(int argc, char* argv[])
+{
+    string line = "";
+
+    for (int y = 0; y < grid_size; y++)
+    {
+        getline(cin, line);
+        for (int x = 0; x < grid_size; x++)
+        {
+            grid[x][y] = (int)(line[x]-'0');
+        }
+    }
+
+    int t = 0;
+    bool all_flashed = false;
+    while(!all_flashed)
+    {
+        all_flashed = true;
+        //Step 1, increment
+        for (int y = 0; y < grid_size; y++)
+        {
+            for (int x = 0; x < grid_size; x++)
+            {
+                ++grid[x][y];
+            }
+        }
+
+        //Step 2, flash
+        bool flashed[grid_size][grid_size] = {false};
+        bool flash_occurred = false;
+        do
+        {
+            flash_occurred = false;
+            for (int y = 0; y < grid_size; y++)
+            {
+                for (int x = 0; x < grid_size; x++)
+                {
+                    if (!flashed[x][y] && grid[x][y] > 9)
+                    {
+                        flashed[x][y] = true;
+                        flash_occurred = true;
+
+                        for(int fy = max(0,y-1); fy < min(grid_size, y+2); fy++)
+                        {
+                            for(int fx = max(0,x-1); fx < min(grid_size,x+2); fx++)
+                            {
+                                grid[fx][fy]++;
+                            }
+                        }
+                    }
+                }
+            }
+        } while (flash_occurred);
+
+        //Step 3, flashed are cleared
+        for (int y = 0; y < grid_size; y++)
+        {
+            for (int x = 0; x < grid_size; x++)
+            {
+                if (flashed[x][y])
+                {
+                    grid[x][y] = 0;
+                }
+                else
+                {
+                    all_flashed = false;
+                }
+            }
+        }
+
+        t++;
+    }
+
+    cout << t << endl;
+}
+
+void output_grid()
+{
+    for (int y = 0; y < grid_size; y++)
+    {
+        for (int x = 0; x < grid_size; x++)
+        {
+            if (0 == grid[x][y])
+            {
+                cout << bold_on << grid[x][y] << bold_off;
+            }
+            else
+            {
+                cout << grid[x][y];
+            }
+        }
+        cout << endl;
+    }
+    cout << endl;
+}
+
+std::ostream& bold_on(std::ostream& os)
+{
+    return os << "\e[1m";
+}
+
+std::ostream& bold_off(std::ostream& os)
+{
+    return os << "\e[0m";
+}

Day 12/part1.cpp

@@ -0,0 +1,72 @@
+#include <iostream>
+#include <cstring>
+#include <string>
+#include <unordered_map>
+#include <set>
+#include <vector>
+#include <algorithm>
+
+using namespace std;
+
+string start = "start";
+string finish = "end";
+
+string lowercase = "qwertyuiopasdfghjklzxcvbnm";
+
+int find_all_paths(unordered_map<string, set<string>> graph, vector<string> current_path);
+
+int main(int argc, char* argv[])
+{
+    unordered_map<string, set<string>> graph;
+
+    string line;
+    while(getline(cin, line))
+    {
+        string::size_type n = line.find("-",0);
+        string node1 = line.substr(0,n);
+        string node2 = line.substr(n+1);
+
+        if (!graph.contains(node1))
+        {
+            graph.emplace(node1, set<string>());
+        }
+
+        if (!graph.contains(node2))
+        {
+            graph.emplace(node2, set<string>());
+        }
+
+        graph[node1].insert(node2);
+        graph[node2].insert(node1);
+    }
+
+    vector<string> beginning_path;
+    beginning_path.push_back(start);
+
+    cout << find_all_paths(graph, beginning_path) << endl;
+}
+
+int find_all_paths(unordered_map<string, set<string>> graph, vector<string> current_path)
+{
+    int found_paths = 0;
+    set<string> connected_nodes = graph[current_path.back()];
+
+    for (set<string>::iterator it = connected_nodes.begin(); it != connected_nodes.end(); ++it)
+    {
+        string current_node = *it;
+
+        if (current_node.compare(finish) == 0)
+        {
+            ++found_paths;
+        }
+        else if (string::npos == current_node.find_first_of(lowercase) ||
+            current_path.end() == std::find(current_path.begin(), current_path.end(), current_node))
+        {   //Big cave or small cave not in path
+            vector<string> next_path(current_path);
+            next_path.push_back(current_node);
+            found_paths += find_all_paths(graph, next_path);
+        }        
+    }
+
+    return found_paths;
+}

Day 12/part2.cpp

@@ -0,0 +1,80 @@
+#include <iostream>
+#include <cstring>
+#include <string>
+#include <unordered_map>
+#include <set>
+#include <vector>
+#include <algorithm>
+
+using namespace std;
+
+string start = "start";
+string finish = "end";
+
+string lowercase = "qwertyuiopasdfghjklzxcvbnm";
+
+int find_all_paths(unordered_map<string, set<string>> graph, vector<string> current_path, bool double_small_taken);
+
+int main(int argc, char* argv[])
+{
+    unordered_map<string, set<string>> graph;
+
+    string line;
+    while(getline(cin, line))
+    {
+        string::size_type n = line.find("-",0);
+        string node1 = line.substr(0,n);
+        string node2 = line.substr(n+1);
+
+        if (!graph.contains(node1))
+        {
+            graph.emplace(node1, set<string>());
+        }
+
+        if (!graph.contains(node2))
+        {
+            graph.emplace(node2, set<string>());
+        }
+
+        if (0 != node2.compare(start))
+            graph[node1].insert(node2);
+        if (0 != node1.compare(start))
+            graph[node2].insert(node1);
+    }
+
+    vector<string> beginning_path;
+    beginning_path.push_back(start);
+
+    cout << find_all_paths(graph, beginning_path, false) << endl;
+}
+
+int find_all_paths(unordered_map<string, set<string>> graph, vector<string> current_path, bool double_small_taken)
+{
+    int found_paths = 0;
+    set<string> connected_nodes = graph[current_path.back()];
+
+    for (set<string>::iterator it = connected_nodes.begin(); it != connected_nodes.end(); ++it)
+    {
+        string current_node = *it;
+
+        if (current_node.compare(finish) == 0)
+        {
+            ++found_paths;
+        }
+        else if (string::npos == current_node.find_first_of(lowercase) ||
+            current_path.end() == std::find(current_path.begin(), current_path.end(), current_node))
+        {   //Big cave or small cave not in path
+            vector<string> next_path(current_path);
+            next_path.push_back(current_node);
+            found_paths += find_all_paths(graph, next_path, double_small_taken);
+        } 
+        else if (!double_small_taken) 
+        {   //Small cave and in path, double is not taken though
+            vector<string> next_path(current_path);
+            next_path.push_back(current_node);
+            found_paths += find_all_paths(graph, next_path, true);
+        }     
+    }
+
+    return found_paths;
+}

Day 13/part1.cpp.cpp

@@ -0,0 +1,79 @@
+#include <iostream>
+#include <string>
+#include <vector>
+#include <set>
+#include <utility>
+
+using namespace std;
+
+set<pair<int,int>> flip_about(set<pair<int,int>> input_points, bool x_flip, int value);
+
+int main(int argc, char* argv[])
+{
+    string line;
+    bool coord_input = true;
+    set<pair<int,int>> coords;
+    vector<pair<bool,int>> folds;
+    while(getline(cin, line))
+    {
+        if (0 == line.size())
+        {
+            coord_input = false;
+            continue;
+        }
+
+        if (coord_input)
+        {
+            string::size_type n = line.find(',');
+            pair<int,int> coord(stoi(line.substr(0,n)), stoi(line.substr(n+1)));
+            coords.insert(coord);
+        }
+        else
+        {
+            string::size_type n = line.find_last_of(' ');
+            line = line.substr(n+1);
+            pair<bool,int> fold(line[0]=='x', stoi(line.substr(2)));
+            folds.push_back(fold);
+        }
+    }
+
+
+    coords = flip_about(coords, folds[0].first, folds[0].second);
+
+    cout << coords.size() << endl;
+}
+
+set<pair<int,int>> flip_about(set<pair<int,int>> input_points, bool x_flip, int value)
+{
+    set<pair<int,int>> output_points;
+    set<pair<int,int>>::iterator it = input_points.begin();
+    for(; it != input_points.end(); ++it)
+    {
+        if (x_flip)
+        {
+            if (it->first > value)
+            {
+                pair<int,int> flipped_coord(2*value-it->first, it->second);
+                output_points.insert(flipped_coord);
+            }
+            else
+            {
+                output_points.insert(*it);
+            }
+        }
+        else
+        {
+            if (it->second > value)
+            {
+                pair<int,int> flipped_coord(it->first, 2*value-it->second);
+                output_points.insert(flipped_coord);
+            }
+            else
+            {
+                output_points.insert(*it);
+            }
+        }
+    }
+
+    return output_points;
+}

Day 13/part2.cpp

@@ -0,0 +1,124 @@
+#include <iostream>
+#include <string>
+#include <vector>
+#include <set>
+#include <utility>
+
+using namespace std;
+
+set<pair<int,int>> flip_about(set<pair<int,int>> input_points, bool x_flip, int value);
+
+int main(int argc, char* argv[])
+{
+    string line;
+    bool coord_input = true;
+    set<pair<int,int>> coords;
+    vector<pair<bool,int>> folds;
+    while(getline(cin, line))
+    {
+        if (0 == line.size())
+        {
+            coord_input = false;
+            continue;
+        }
+
+        if (coord_input)
+        {
+            string::size_type n = line.find(',');
+            pair<int,int> coord(stoi(line.substr(0,n)), stoi(line.substr(n+1)));
+            coords.insert(coord);
+        }
+        else
+        {
+            string::size_type n = line.find_last_of(' ');
+            line = line.substr(n+1);
+            pair<bool,int> fold(line[0]=='x', stoi(line.substr(2)));
+            folds.push_back(fold);
+        }
+    }
+
+    for (unsigned int i = 0; i < folds.size(); i++)
+    {
+        coords = flip_about(coords, folds[i].first, folds[i].second);
+    }
+
+    int xmax = 0, ymax = 0;
+    for (set<pair<int,int>>::iterator it = coords.begin(); it != coords.end(); ++it)
+    {
+        if (it->first > xmax)
+        {
+            xmax = it->first;
+        }
+        if (it->second > ymax)
+        {
+            ymax = it->second;
+        }
+    }
+    ++xmax;
+    ++ymax;
+
+    bool** marked = new bool*[xmax];
+    for(int x = 0; x < xmax; x++)
+    {
+        marked[x] = new bool[ymax];
+        for(int y = 0; y < ymax; y++)
+        {
+            marked[x][y] = false;
+        }
+    }
+
+    for (set<pair<int,int>>::iterator it = coords.begin(); it != coords.end(); ++it)
+    {
+        marked[it->first][it->second] = true;
+    }
+
+    for (int y = 0; y < ymax; y++)
+    {
+        for (int x = 0; x < xmax; x++)
+        {
+            cout << (marked[x][y]?"#":" ");
+        }
+        cout << endl;
+    }
+    
+    for(int x = 0; x < xmax; x++)
+    {
+        delete[] marked[x];
+    }
+    delete[] marked;
+}
+
+set<pair<int,int>> flip_about(set<pair<int,int>> input_points, bool x_flip, int value)
+{
+    set<pair<int,int>> output_points;
+    set<pair<int,int>>::iterator it = input_points.begin();
+    for(; it != input_points.end(); ++it)
+    {
+        if (x_flip)
+        {
+            if (it->first > value)
+            {
+                pair<int,int> flipped_coord(2*value-it->first, it->second);
+                output_points.insert(flipped_coord);
+            }
+            else
+            {
+                output_points.insert(*it);
+            }
+        }
+        else
+        {
+            if (it->second > value)
+            {
+                pair<int,int> flipped_coord(it->first, 2*value-it->second);
+                output_points.insert(flipped_coord);
+            }
+            else
+            {
+                output_points.insert(*it);
+            }
+        }
+    }
+
+    return output_points;
+}

Day 14/part1.cpp

@@ -0,0 +1,125 @@
+#include <iostream>
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+using namespace std;
+
+unordered_map<char, unsigned long long> get_count_after_reaction(unordered_map<string, char> reactions, string pair, int reaction_iterations);
+
+int main(int argc, char* argv[])
+{
+    string polymer;
+    getline(cin, polymer);
+
+    unordered_map<string, char> reactions;
+
+    string line;
+    getline(cin, line);
+    while(getline(cin, line))
+    {
+        reactions[line.substr(0,2)] = line[line.size()-1];
+    }
+
+    unordered_map<char, unsigned long long> counts;
+    for(int i = 0; i < polymer.size(); i++)
+    {
+        counts[polymer[i]] = 0;
+    }
+
+    for(int i = 0; i < polymer.size(); i++)
+    {
+        counts[polymer[i]]++;
+    }
+
+    for(int i = 0; i < polymer.size()-1; i++)
+    {
+        string pair = polymer.substr(i,2);
+        unordered_map<char, unsigned long long> pair_counts = get_count_after_reaction(reactions, pair, 10);
+
+        for(auto &it : pair_counts)
+        {
+            if (!counts.contains(it.first))
+            {
+                counts[it.first] = 0;
+            }
+
+            counts[it.first] += it.second;
+        }
+    }
+
+    vector<unsigned long long> counts_list;
+    for (auto &it : counts)
+    {
+        cout << it.first << " " << it.second << endl;
+        counts_list.push_back(it.second);
+    }
+
+    sort(counts_list.begin(), counts_list.end());
+
+    cout << counts_list[counts_list.size()-1]-counts_list[0] << endl;
+}
+
+unordered_map<char, unsigned long long> get_count_after_reaction(unordered_map<string, char> reactions, string pair, int reaction_iterations)
+{
+    static unordered_map<string, vector<unordered_map<char, unsigned long long>>> reaction_cache;
+
+    if (0 == reaction_iterations)
+    {
+        return unordered_map<char, unsigned long long>();
+    }
+
+    if (!reaction_cache.contains(pair))
+    {
+        reaction_cache[pair] = vector<unordered_map<char, unsigned long long>>();
+    }
+
+    if (reaction_cache[pair].size() >= reaction_iterations)
+    {
+        if (reaction_cache[pair][reaction_iterations-1].size() != 0)
+        {
+            return reaction_cache[pair][reaction_iterations-1];
+        }
+    }
+    else
+    {
+        unsigned int old_size = reaction_cache[pair].size();
+        for (unsigned int current_size = old_size; current_size < reaction_iterations; current_size++)
+        {
+            reaction_cache[pair].push_back(unordered_map<char,unsigned long long>());
+        }
+    }
+
+    unordered_map<char, unsigned long long> out_counts;
+    out_counts[reactions[pair]] = 1;
+
+    string left_pair = pair.substr(0,1) + reactions[pair];
+    string right_pair = reactions[pair] + pair.substr(1,1);
+
+    unordered_map<char, unsigned long long> left_counts = get_count_after_reaction(reactions, left_pair, reaction_iterations-1);
+    unordered_map<char, unsigned long long> right_counts = get_count_after_reaction(reactions, right_pair, reaction_iterations-1);
+
+    for (auto &it : left_counts)
+    {
+        if (!out_counts.contains(it.first))
+        {
+            out_counts[it.first] = 0;
+        }
+
+        out_counts[it.first] += it.second;
+    }
+
+    for (auto &it : right_counts)
+    {
+        if (!out_counts.contains(it.first))
+        {
+            out_counts[it.first] = 0;
+        }
+
+        out_counts[it.first] += it.second;
+    }
+
+    reaction_cache[pair][reaction_iterations-1] = out_counts;
+
+    return out_counts;
+}

Day 14/part2.cpp

@@ -0,0 +1,125 @@
+#include <iostream>
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+using namespace std;
+
+unordered_map<char, unsigned long long> get_count_after_reaction(unordered_map<string, char> reactions, string pair, int reaction_iterations);
+
+int main(int argc, char* argv[])
+{
+    string polymer;
+    getline(cin, polymer);
+
+    unordered_map<string, char> reactions;
+
+    string line;
+    getline(cin, line);
+    while(getline(cin, line))
+    {
+        reactions[line.substr(0,2)] = line[line.size()-1];
+    }
+
+    unordered_map<char, unsigned long long> counts;
+    for(int i = 0; i < polymer.size(); i++)
+    {
+        counts[polymer[i]] = 0;
+    }
+
+    for(int i = 0; i < polymer.size(); i++)
+    {
+        counts[polymer[i]]++;
+    }
+
+    for(int i = 0; i < polymer.size()-1; i++)
+    {
+        string pair = polymer.substr(i,2);
+        unordered_map<char, unsigned long long> pair_counts = get_count_after_reaction(reactions, pair, 40);
+
+        for(auto &it : pair_counts)
+        {
+            if (!counts.contains(it.first))
+            {
+                counts[it.first] = 0;
+            }
+
+            counts[it.first] += it.second;
+        }
+    }
+
+    vector<unsigned long long> counts_list;
+    for (auto &it : counts)
+    {
+        cout << it.first << " " << it.second << endl;
+        counts_list.push_back(it.second);
+    }
+
+    sort(counts_list.begin(), counts_list.end());
+
+    cout << counts_list[counts_list.size()-1]-counts_list[0] << endl;
+}
+
+unordered_map<char, unsigned long long> get_count_after_reaction(unordered_map<string, char> reactions, string pair, int reaction_iterations)
+{
+    static unordered_map<string, vector<unordered_map<char, unsigned long long>>> reaction_cache;
+
+    if (0 == reaction_iterations)
+    {
+        return unordered_map<char, unsigned long long>();
+    }
+
+    if (!reaction_cache.contains(pair))
+    {
+        reaction_cache[pair] = vector<unordered_map<char, unsigned long long>>();
+    }
+
+    if (reaction_cache[pair].size() >= reaction_iterations)
+    {
+        if (reaction_cache[pair][reaction_iterations-1].size() != 0)
+        {
+            return reaction_cache[pair][reaction_iterations-1];
+        }
+    }
+    else
+    {
+        unsigned int old_size = reaction_cache[pair].size();
+        for (unsigned int current_size = old_size; current_size < reaction_iterations; current_size++)
+        {
+            reaction_cache[pair].push_back(unordered_map<char,unsigned long long>());
+        }
+    }
+
+    unordered_map<char, unsigned long long> out_counts;
+    out_counts[reactions[pair]] = 1;
+
+    string left_pair = pair.substr(0,1) + reactions[pair];
+    string right_pair = reactions[pair] + pair.substr(1,1);
+
+    unordered_map<char, unsigned long long> left_counts = get_count_after_reaction(reactions, left_pair, reaction_iterations-1);
+    unordered_map<char, unsigned long long> right_counts = get_count_after_reaction(reactions, right_pair, reaction_iterations-1);
+
+    for (auto &it : left_counts)
+    {
+        if (!out_counts.contains(it.first))
+        {
+            out_counts[it.first] = 0;
+        }
+
+        out_counts[it.first] += it.second;
+    }
+
+    for (auto &it : right_counts)
+    {
+        if (!out_counts.contains(it.first))
+        {
+            out_counts[it.first] = 0;
+        }
+
+        out_counts[it.first] += it.second;
+    }
+
+    reaction_cache[pair][reaction_iterations-1] = out_counts;
+
+    return out_counts;
+}