3 files changed, 30 insertions, 7 deletions
diff --git a/src/2018/day3/aoc.cpp b/src/2018/day3/aoc.cpp
index c5aa403..3ea5432 100644
--- a/src/2018/day3/aoc.cpp
+++ b/src/2018/day3/aoc.cpp
@@ -2,14 +2,23 @@
 
 namespace aoc2018 {
 
-int day3(line_view file, int x) {
+std::pair<int, int> day3(line_view file, int x) {
+
   fabric* f = new fabric;
-  per_line(file, [&f](line_view lv) {
-    f->parse(lv);
+  std::vector<claim> cs;
+  per_line(file, [&f, &cs](line_view lv) {
+    f->parse(lv, cs);
     return true;
   });
 
-  return f->count(x);
+  int id{0};
+  for (auto& c : cs) {
+    if (!f->overlap(c)) {
+      id = c.id;
+    }
+  }
+
+  return {f->count(x), id};
 }
 
 } // namespace aoc2018
diff --git a/src/2018/day3/aoc.h b/src/2018/day3/aoc.h
index 24fad47..42b3c90 100644
--- a/src/2018/day3/aoc.h
+++ b/src/2018/day3/aoc.h
@@ -34,6 +34,17 @@ struct fabric {
     return total;
   }
 
+  bool overlap(const claim& c) {
+    for (int x = c.x; x < c.x + c.width; x++) {
+      for (int y = c.y; y < c.y + c.height; y++) {
+        if (claims[y * 1000 + x] > 1) {
+          return true;
+        }
+      }
+    }
+    return false;
+  }
+
   void get_number(const char** pp, int* is[], int i) {
     *is[i] = 0;
     const char* p = *pp;
@@ -44,7 +55,7 @@ struct fabric {
     *pp = p;
   }
 
-  void parse(line_view lv) {
+  void parse(line_view lv, std::vector<claim>& cs) {
     claim c;
     int* is[] = {&c.id, &c.x, &c.y, &c.width, &c.height};
     int i{0};
@@ -56,9 +67,10 @@ struct fabric {
       p++;
     }
     apply(c);
+    cs.push_back(c);
   }
 };
 
-int day3(line_view, int);
+std::pair<int, int> day3(line_view, int);
 
 } // namespace aoc2018
diff --git a/test/test_2018.cpp b/test/test_2018.cpp
index db1c037..f6c61bd 100644
--- a/test/test_2018.cpp
+++ b/test/test_2018.cpp
@@ -24,5 +24,7 @@ TEST_CASE("Inventory Management System", "[2018]") {
 
 TEST_CASE("No Matter How You Slice It", "[2018]") {
   line_view lv = load_file("../src/2018/day3/input");
-  REQUIRE(109785 == aoc2018::day3(lv, 1));
+  auto p = aoc2018::day3(lv, 1);
+  REQUIRE(109785 == p.first);
+  REQUIRE(504 == p.second);
 }