1 files changed, 44 insertions, 0 deletions
diff --git a/src/2019/day6/aoc.cpp b/src/2019/day6/aoc.cpp
index f0cbc1b..e0a8cac 100644
--- a/src/2019/day6/aoc.cpp
+++ b/src/2019/day6/aoc.cpp
@@ -1,5 +1,49 @@
 #include "aoc.h"
+#include <unordered_map>
+#include <vector>
 
 namespace aoc2019 {
 
+star* find(std::unordered_map<line_view, star*>& stars, line_view lv) {
+  auto it = stars.find(lv);
+  star* s = nullptr;
+  if (it == stars.end()) {
+    s = new star{lv};
+    stars.insert({lv, s});
+  } else {
+    s = it->second;
+  }
+  // std::cout << s->name << std::endl;
+  return s;
 }
+
+void count(star* s, std::vector<star*>& vs, int* total) {
+  std::cout << s->name << std::endl;
+  if (s->orbits.size() > 0) {
+    std::vector<star*> orbits{s->orbits.begin(), s->orbits.end()};
+    for (auto& x : orbits) {
+      vs.push_back(x);
+      count(x, vs, total);
+      vs.pop_back();
+    }
+  }
+  *total += vs.size();
+}
+
+int day6(line_view file) {
+  std::unordered_map<line_view, star*> stars;
+  per_line(file, [&stars](line_view lv) {
+    const char* p = lv.contains(")");
+    star* s1 = find(stars, line_view{lv.line, p});
+    star* s2 = find(stars, line_view{p + 1, lv.line + lv.length - 1});
+    s1->orbits.insert(s2);
+    return true;
+  });
+
+  int total{0};
+  std::vector<star*> vs;
+  count(stars["COM"], vs, &total);
+  return total;
+}
+
+} // namespace aoc2019