Added older advents

advent_of_code_2018/day10/main1.cc

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+#include "main.ih"
+
+struct Star
+{
+    Position pos;
+    Velocity vel;
+
+    void update()
+    {
+        pos = pos + vel;
+    }
+};
+
+Star read_star()
+{
+    Star rval;
+    cin >> rval.pos;
+    cin >> rval.vel;
+    return rval;
+}
+
+size_t grid_size(vector<Star> const &stars)
+{
+    int minx = numeric_limits<int>::max();
+    int maxx = numeric_limits<int>::min();
+    int miny = minx;
+    int maxy = maxx;
+
+    for (Star const &star : stars)
+    {
+        minx = min(minx, star.pos.xpos);
+        maxx = max(maxx, star.pos.xpos);
+        miny = min(miny, star.pos.ypos);
+        maxy = max(maxy, star.pos.ypos);
+    }
+
+    size_t width = maxx - minx + 1;
+    size_t height = maxy - miny + 1;
+    return width * height;
+}
+
+void write_to_console(vector<Star> const &stars)
+{
+    int minx = numeric_limits<int>::max();
+    int maxx = numeric_limits<int>::min();
+    int miny = minx;
+    int maxy = maxx;
+
+    for (Star const &star : stars)
+    {
+        minx = min(minx, star.pos.xpos);
+        maxx = max(maxx, star.pos.xpos);
+        miny = min(miny, star.pos.ypos);
+        maxy = max(maxy, star.pos.ypos);
+    }
+
+    int xpos = minx;
+    int ypos = miny;
+    int width = maxx - minx + 1;
+    int height = maxy - miny + 1;
+    vector<vector<bool>> grid;
+    grid.resize(width, vector<bool>(height));
+
+    for (Star const &star : stars)
+        grid[star.pos.xpos - xpos][star.pos.ypos - ypos] = true;
+
+    for (int idy = 0; idy < height; ++idy)
+    {
+        for (int idx = 0; idx < width; ++idx)
+            cout << (grid[idx][idy] ? '#' : ' ');
+        cout << "\n";
+    }
+}
+
+int main()
+{
+    vector<Star> stars;
+
+    while (!cin.eof())
+        stars.push_back(read_star());
+
+    size_t size = grid_size(stars);
+    for (size_t time = 0; true; ++time)
+    {
+        vector<Star> next_position(stars);
+        for (Star &star : next_position)
+            star.update();
+
+        size_t next_size = grid_size(next_position);
+
+        if (next_size > size)
+        {
+            write_to_console(stars);
+            cout << "That took " << time << " seconds!\n"; // part 2
+            return 0;
+        }
+
+        stars.swap(next_position);
+        size = next_size;
+    }
+}