1 files changed, 29 insertions, 4 deletions
diff --git a/src/2015/day19/aoc.cpp b/src/2015/day19/aoc.cpp
index af42b23..019a120 100644
--- a/src/2015/day19/aoc.cpp
+++ b/src/2015/day19/aoc.cpp
@@ -13,10 +13,35 @@ std::pair<int, int> day19(line_view file) {
   // int shortest = INT32_MAX;
   // m.deduct(m.original, 0, &shortest);
   // m.transfer("e", 0, &shortest);
-  std::vector<molecule::pattern> ps;
-  const char* x = nullptr;
-  m.parse_pattern(m.original, 0, ps, &x);
-  std::for_each(ps.begin(), ps.end(), [](molecule::pattern p) { std::cout << p.depth << " -> " << p.lv << std::endl; });
+  int steps = 0;
+
+  line_view lv = m.original;
+
+  do {
+    lv = m.replace(lv, &steps);
+    printf("%d\n", steps);
+
+    std::vector<molecule::pattern> ps;
+    const char* x = nullptr;
+    m.parse_pattern(lv, 0, ps, &x);
+    std::for_each(ps.begin(), ps.end(),
+                  [](molecule::pattern p) { std::cout << p.depth << " -> " << p.lv << std::endl; });
+    if (ps[0].lv.contains("Y")) {
+      std::vector<line_view> ys;
+      m.parse_y(ps[0].lv, ys);
+      for (auto y : ys) {
+        if (m.transfers.find(y) == m.transfers.end()) {
+          line_view to = m.deduce(y, &steps);
+          lv = m.replace(lv, {y, to}, y.line);
+          break;
+        }
+      }
+    } else {
+      line_view to = m.deduce(ps[0].lv, &steps);
+      lv = m.replace(lv, {ps[0].lv, to}, ps[0].lv.line);
+    }
+  } while (true);
+
   return {m.distinct(changes), 0};
 }