1 files changed, 69 insertions, 1 deletions
diff --git a/src/2015/day19/aoc.h b/src/2015/day19/aoc.h
index b1ba95c..b357ab1 100644
--- a/src/2015/day19/aoc.h
+++ b/src/2015/day19/aoc.h
@@ -1,6 +1,74 @@
 #pragma once
 
 #include "common.h"
+#include <map>
+#include <vector>
 
 namespace aoc2015 {
-}
+
+struct replacement {
+  line_view from;
+  line_view to;
+};
+
+struct molecule {
+  std::vector<replacement> replacements;
+  line_view original;
+
+  struct change {
+    size_t i;
+    replacement c;
+  };
+
+  void check(size_t i, replacement r, std::map<int, std::vector<change>>& vr) const noexcept {
+    const char* p1 = original.line;
+    const char* p2 = original.line + original.length;
+    do {
+      line_view lv = line_view{p1, p2};
+      const char* p = lv.contains(r.from);
+      // std::cout << lv << ": " << r.from << " -> " << r.to << std::endl;
+      if (p != nullptr) {
+        vr[r.to.length - r.from.length].push_back({i, {line_view{p, r.from.length}, r.to}});
+        p1 = p + r.from.length;
+      } else {
+        break;
+      }
+    } while (p1 < p2);
+  }
+
+  void check(std::map<int, std::vector<change>>& vr) const noexcept {
+    for (size_t i = 0; i < replacements.size(); i++) {
+      check(i, replacements[i], vr);
+    }
+  }
+
+  int distinct(const std::vector<change>& vc) const noexcept {
+    for (auto& c : vc) {
+      std::cout << c.i << ": " << original << " " << (c.c.from.line - original.line) << " " << c.c.to << std::endl;
+    }
+    return 0;
+  }
+
+  int distinct(const std::map<int, std::vector<change>>& vr) const noexcept {
+    int d{0};
+    for (auto& kv : vr) {
+      d += distinct(kv.second);
+    }
+    return d;
+  }
+
+  void parse(line_view lv) {
+    const char* p = lv.contains("=>");
+    if (p != nullptr) {
+      replacements.push_back({{lv.line, p - 1}, {p + 3, lv.line + lv.length - 1}});
+    } else {
+      if (lv.length > 1) {
+        original = {lv.line, lv.line + lv.length - 1};
+      }
+    }
+  }
+};
+
+int day19(line_view);
+
+} // namespace aoc2015