Added older advents

advent_of_code_2018/day7/main2.cc

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+#include <algorithm>
+#include <array>
+#include <iostream>
+#include <string>
+#include <vector>
+
+#include <chrono>
+#include <thread>
+#include <unistd.h>
+
+using namespace std;
+
+struct Constraint
+{
+    bool placed = false;
+    vector<char> requires;
+    vector<char> required_by;
+};
+
+struct Task
+{
+    char step = '\0';
+    size_t time_left = 0;
+};
+
+bool satisfied(Constraint const &constraint, string const &plan)
+{
+    for (char c : constraint.requires)
+    {
+        if (plan.find(c) == string::npos)
+        {
+            cout << "Constraint not met in plan '" << plan << "', missing " << c << "\n";
+            return false;
+        }
+    }
+    return true;
+}
+
+char find_satisfied(array<Constraint, 26> const &constraints, string const&plan, string const&goal)
+{
+    cout << "Finding next step from plan '" << plan << "', already done: '" << goal << "'\n";
+
+    for (char c : plan)
+    {
+        if (satisfied(constraints[c - 'A'], goal))
+            return c;
+    }
+
+    return 0;
+}
+
+int main()
+{
+    array<Constraint, 26> constraints {};
+    size_t plansize = 26;
+    size_t baseline = 60;
+
+    while (!cin.eof())
+    {
+        char step;
+        char requires;
+
+        cin.ignore(5); // 'Step '
+        cin >> requires;
+        cin.ignore(30); // ' must be finished before step '
+        cin >> step;
+        cin.ignore(12); //' can begin.\n'
+
+        cout << step << " requires " << requires << "\n";
+        constraints[step - 'A'].requires.push_back(requires);
+        constraints[requires - 'A'].required_by.push_back(step);
+    }
+
+    string plan;
+    while(plan.size() != plansize)
+    {
+        for (size_t idx = 0; idx < 26; ++idx)
+        {
+            if (!constraints[idx].placed && satisfied(constraints[idx], plan))
+            {
+                plan += static_cast<char>('A' + idx);
+                constraints[idx].placed = true;
+                break;
+            }
+        }
+
+        cout << plan.size() << " / '" << plan << "'\n";
+    }
+
+    cout << plan.size() << " / '" << plan << "'\n";
+
+    /************************************/
+    /************************************/
+    /************************************/
+    string done;
+    Task workers[5];
+    size_t duration = 0;
+
+    while (done.size() != plansize)
+    {
+        ++duration;
+        for(Task &task : workers)
+            if (task.time_left != 0) --task.time_left;
+
+        for (Task &task : workers)
+        {
+            if (task.time_left == 0 && task.step != '\0')
+            {
+                done += task.step;
+                task.step = '\0';
+            }
+        }
+
+        for (Task &task : workers)
+        {
+            char next = find_satisfied(constraints, plan, done);
+            if (next == 0) break;
+
+            if (task.time_left == 0)
+            {
+                if (plan.size() > 0 && satisfied(constraints[next - 'A'], done))
+                {
+                    task.time_left = baseline + (next - 'A') + 1;
+                    task.step = next;
+                    plan.erase(plan.find(next), 1);
+                }
+            }
+        }
+
+        cout << "Plan / Done: '" << plan << "' / '" << done << "'\n";
+        cout << "Workers on: \n";
+        for (Task &task : workers)
+        {
+            cout << "     Step: " << (task.step == '\0' ? '-' : task.step) << "\n";
+            cout << "     Time: " << task.time_left << "\n";
+        }
+        cout << "\n";
+        // this_thread::sleep_for(std::chrono::milliseconds(1000));
+    }
+
+    cout << "Total time: " << duration << "s \n";
+}