Day 5

d5/main.cxx

@@ -1,15 +1,145 @@
 #include <iostream>
-#include <fstream>
+#include <sstream>
+#include <unordered_map>
+#include <vector>
+#include <string>
+#include <algorithm> 
+#include <chrono>
 
 using std::cout, std::endl;
 
-int main() {
-    std::ifstream file{"../d5/input.txt"};
+constexpr const char content[] = {
+    #embed "input.txt"
+};
+
+int part_1() {
+    std::istringstream input_stream(content);
     std::string line;
+    std::unordered_map<int, std::vector<int>> pages = {};
+    std::vector<std::vector<int>> updates = {}; 
 
-    while (std::getline(file, line)) {
 
+    while (std::getline(input_stream, line)) {
+       if(line.empty()) {
+           break;
+       }
+       auto fst_page = std::stoi(line.substr(0, 2));
+       auto snd_page = std::stoi(line.substr(3, 4));
+       if(pages.find(fst_page) == pages.end()) {
+           pages[fst_page] = {};
+       }
+       pages[snd_page].emplace_back(fst_page);
     }
 
+    while (std::getline(input_stream, line)) {
+        size_t start{0}, end{0};
+        std::vector<int> update = {};
+        while(true) {
+            end = line.find(",", start);
+            if(end == std::string::npos) {
+                update.push_back(std::stoi(line.substr(start, end)));
+                break;
+            }
+            update.push_back(std::stoi(line.substr(start, end)));
+            start = end + 1;
+        }
+        updates.push_back(update);
+    }
+
+    int acc{0};
+    for(const auto& update : updates) {
+        bool invalid_update = false;
+        for(auto num_it = update.begin(); num_it != update.end(); num_it++) {
+            auto num = *num_it;
+            invalid_update = std::find_if(pages[num].begin(), pages[num].end(), [&update, num_it](int precede_num) {
+                    auto precede_it = std::find(update.begin(), update.end(), precede_num);
+                    if(precede_it != update.end() && precede_it > num_it) {
+                        return true;
+                    } else {
+                        return false;
+                    }
+            }) != pages[num].end();  
+            
+
+            if(invalid_update) {
+                break;
+            } 
+        }
+
+        int middle_size = update[update.size() / 2];
+        if(!invalid_update) {
+            acc += middle_size;
+        }
+    }
+    return acc;
+}
+
+int part_2() {
+    std::istringstream input_stream(content);
+    std::string line;
+    std::unordered_map<int, std::vector<int>> pages = {};
+    std::vector<std::vector<int>> updates = {}; 
+
+    while (std::getline(input_stream, line)) {
+       if(line.empty()) {
+           break;
+       }
+       auto fst_page = std::stoi(line.substr(0, 2));
+       auto snd_page = std::stoi(line.substr(3, 4));
+       if(pages.find(fst_page) == pages.end()) {
+           pages[fst_page] = {};
+       }
+       pages[snd_page].emplace_back(fst_page);
+    }
+
+    while (std::getline(input_stream, line)) {
+        size_t start{0}, end{0};
+        std::vector<int> update = {};
+        while(true) {
+            end = line.find(",", start);
+            if(end == std::string::npos) {
+                update.push_back(std::stoi(line.substr(start, end)));
+                break;
+            }
+            update.push_back(std::stoi(line.substr(start, end)));
+            start = end + 1;
+        }
+        updates.push_back(update);
+    }
+
+    int acc{0};
+    for(std::vector<int>& update : updates) {
+        bool invalid_update = false;
+
+        std::sort(update.begin(), update.end(), [&invalid_update, update, &pages](int a, int b) {
+            bool contains = std::find(pages[b].begin(), pages[b].end(), a) != pages[b].end();
+            if(contains) {
+                auto start_it = std::find(update.begin(), update.end(), b);
+                for(auto cmp_num = start_it + 1; cmp_num != update.end(); cmp_num++) {
+                    if(*cmp_num == a) {
+                        invalid_update = true;
+                        return true;
+                    }
+                }
+            }
+            return false;
+        });
+
+        int middle_size = update[update.size() / 2];
+        if(invalid_update) {
+            acc += middle_size;
+        }
+    }
+    return acc;
+} 
+
+int main() {
+    std::chrono::steady_clock::time_point begin = std::chrono::steady_clock::now();
+    auto p1_val = part_1();
+    std::chrono::steady_clock::time_point middle = std::chrono::steady_clock::now();
+    auto p2_val = part_2();
+    std::chrono::steady_clock::time_point end = std::chrono::steady_clock::now();
+    cout << "Part 1: " << p1_val << " (" << std::chrono::duration_cast<std::chrono::microseconds>(middle - begin).count() << "µs)" << endl;  
+    cout << "Part 2: " << p2_val << " (" << std::chrono::duration_cast<std::chrono::microseconds>(end - middle).count() << "µs)" << endl;
     return 0;
 }