Move c++ solutions into separate directory

2024/cpp/day-05/main.cpp

@@ -0,0 +1,97 @@
+#include <algorithm>
+#include <iostream>
+#include <sstream>
+#include <vector>
+
+using namespace std;
+
+vector<pair<int, int>> readRules()
+{
+    vector<pair<int, int>> rules;
+    string line;
+    while (getline(cin, line)) {
+        if (line == "") {
+            break;
+        }
+        int number1 = stoi(line.substr(0, 2));
+        int number2 = stoi(line.substr(3, 2));
+        rules.push_back({number1, number2});
+    }
+    return rules;
+}
+
+vector<vector<int>> readManuals()
+{
+    vector<vector<int>> manuals;
+    string line;
+    while (getline(cin, line)) {
+        stringstream inStream(line);
+        vector<int> pages;
+        string page;
+        while (getline(inStream, page, ',')) {
+            pages.push_back(stoi(page));
+        }
+        manuals.push_back(pages);
+    }
+    return manuals;
+}
+
+bool isCorrectPageOrdering(const int firstPage,
+                           const int secondPage,
+                           const vector<pair<int, int>> &rules)
+{
+    auto it = lower_bound(rules.begin(),
+                          rules.end(),
+                          secondPage,
+                          [](const pair<int, int> &a, int b) { return a.first < b; });
+
+    for (; it != rules.end() && it->first == secondPage; ++it) {
+        if (it->second == firstPage) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
+vector<int> getProperlyOrderedPages(vector<int> pages, const vector<pair<int, int>> &rules)
+{
+    sort(pages.begin(), pages.end(), [&rules](int a, int b) {
+        return isCorrectPageOrdering(a, b, rules);
+    });
+    return pages;
+}
+
+int getMiddlePageNumber(const vector<int> &pages)
+{
+    size_t middleIndex = pages.size() / 2;
+    return pages[middleIndex];
+}
+
+int main()
+{
+    vector<pair<int, int>> rules = readRules();
+    vector<vector<int>> manuals = readManuals();
+    sort(rules.begin(), rules.end());
+
+    int sumOfCorrectMiddlePages = 0;
+    int sumOfCorrectedMiddlePages = 0;
+
+    for (const vector<int> &pages : manuals) {
+        const vector<int> properlyOrderedPages = getProperlyOrderedPages(pages, rules);
+        if (pages == properlyOrderedPages) {
+            sumOfCorrectMiddlePages += getMiddlePageNumber(pages);
+        } else {
+            sumOfCorrectedMiddlePages += getMiddlePageNumber(properlyOrderedPages);
+        }
+    }
+
+    // Part one
+    cout << "Sum of the middle page numbers of all correctly ordered manuals: "
+         << sumOfCorrectMiddlePages << endl;
+
+    // Part two
+    cout
+        << "Sum of the middle page numbers of all incorrectly ordered manuals after ordering them: "
+        << sumOfCorrectedMiddlePages << endl;
+}