traverse lap

2 files changed, 38 insertions, 7 deletions

diff --git a/src/2018/day6/aoc.cpp b/src/2018/day6/aoc.cpp
index 5350b0e..07f8ad9 100644
--- a/src/2018/day6/aoc.cpp
+++ b/src/2018/day6/aoc.cpp
@@ -26,10 +26,40 @@ int day6(line_view file) {
     p.distance = 0;
 
     std::vector<int> total = {0};
-    c.traverse([&total, &b, &c](int lap, int dir, coordinate x) { return true; },
-               [&total]() { return total[total.size() - 1] == 0; });
+
+    auto f = [&total, &b, &c, &i](size_t lap, coordinate x) {
+      if (x.x >= 0 && x.x <= b.cols && x.y >= 0 && x.y <= b.rows) {
+        if (lap == total.size()) {
+          total.push_back(0);
+        }
+        auto& p = b.ps[x.y * b.rows + x.x];
+        int d = x.distance(c);
+        if (d < p.distance) {
+          p.id = i;
+          p.distance = d;
+          total[lap] += 1;
+        }
+        if (d == p.distance) {
+          p.id = -2; // same distance
+          total[lap] += 1;
+        }
+      }
+      return true;
+    };
+    auto g = [&total]() { return total[total.size() - 1] == 0; };
+    c.traverse(f, g);
+  }
+
+  std::vector<int> xs(cs.size(), 0);
+  b.count(xs);
+
+  int max{INT32_MIN};
+  for (auto& x : xs) {
+    if (x != INT32_MAX && x > max) {
+      max = x;
+    }
   }
-  return 0;
+  return max;
 }
 
 } // namespace aoc2018
diff --git a/src/2018/day6/aoc.h b/src/2018/day6/aoc.h
index 5d27936..9bb86d7 100644
--- a/src/2018/day6/aoc.h
+++ b/src/2018/day6/aoc.h
@@ -54,14 +54,14 @@ struct coordinate {
       return (c.*(fs[i]))(1);
     };
     int steps[] = {1, 1, 2, 2};
-    int i{0};
+    size_t i{0};
     coordinate c = *this;
     bool stop{false};
     while (!stop) {
       int s = i % 4;
       for (int x = 0; x < steps[s] && !stop; x++) {
         c = next(s, c);
-        stop = !f(i / 4, s, c, std::forward<Args>(args)...);
+        stop = !f(i / 4, c, std::forward<Args>(args)...);
       }
       steps[s] += 2;
       i++;
@@ -81,7 +81,7 @@ struct space_board {
   int rows;
   int cols;
   std::vector<point> ps;
-  space_board(int x, int y) : rows(x), cols(y), ps(x * y, {-1, INT32_MAX}){};
+  space_board(int x, int y) : rows(y), cols(x), ps(x * y, {-1, INT32_MAX}){};
 
   void count(std::vector<int>& area) {
     for (int y = 0; y < cols; y++) {
@@ -89,7 +89,8 @@ struct space_board {
         auto p = ps[y * rows + x];
         if (x == 0 || y == 0 || x == rows - 1 || y == cols - 1) {
           area[p.id] = INT32_MAX;
-        } else {
+        }
+        if (area[p.id] < INT32_MAX) {
           area[p.id] += 1;
         }
       }