1 files changed, 83 insertions, 0 deletions

diff --git a/2024/05/day05b.cpp b/2024/05/day05b.cpp
new file mode 100644
index 0000000..d9168ac
--- /dev/null
+++ b/2024/05/day05b.cpp
@@ -0,0 +1,83 @@
+#include <algorithm>
+#include <iostream>
+#include <sstream>
+#include <string>
+#include <string_view>
+#include <set>
+#include <vector>
+using namespace std;
+
+vector<int> readints(string &s) {
+        vector<int> v;
+        stringstream sin(s);
+        int x;
+
+        while (sin >> x)
+                v.push_back(x);
+
+        return v;
+}
+
+bool valid(vector<int> &v, vector<pair<int, int>> &rules) {
+        for (unsigned i = 0; i < v.size(); i++)
+                for (unsigned j = i+1; j < v.size(); j++)
+                        for (auto r : rules)
+                                if (v[i] == r.second && v[j] == r.first)
+                                        return false;
+        return true;
+}
+
+bool canbenext(int x, vector<int> &v, bool picked[], vector<pair<int, int>> &rules) {
+        for (unsigned i = 0; i < v.size(); i++) {
+                if (picked[i])
+                        continue;
+                for (auto r : rules)
+                        if (r.first == v[i] && r.second == x)
+                                return false;
+        }
+
+        return true;
+}
+
+vector<int> sort(vector<int> &v, vector<pair<int, int>> &rules) {
+        vector<int> w;
+        bool picked[v.size()] = { 0 };
+
+        while (w.size() < v.size()) {
+                for (unsigned i = 0; i < v.size(); i++) {
+                        if (!picked[i] && canbenext(v[i], v, picked, rules)) {
+                                picked[i] = true;
+                                w.push_back(v[i]);
+                        }
+                }
+        }
+
+        return w;
+}
+
+int main() {
+        string line;
+        vector<pair<int, int>> rules;
+        while (getline(cin, line)) {
+                if (line == "")
+                        break;
+
+                replace(line.begin(), line.end(), '|', ' ');
+                auto v = readints(line);
+                int x = v[0];
+                int y = v[1];
+                rules.push_back(make_pair(x, y));
+        }
+
+        int tot = 0;
+        while (getline(cin, line)) {
+                replace(line.begin(), line.end(), ',', ' ');
+                auto v = readints(line);
+                if (!valid(v, rules)) {
+                        auto w = sort(v, rules);
+                        tot += w[w.size()/2];
+                }
+        }
+        cout << tot << endl;
+        return 0;
+}