diff --git a/2015/01.cpp b/2015/01.cpp
new file mode 100644
index 0000000..ae2cf05
--- /dev/null
+++ b/2015/01.cpp
@@ -0,0 +1,35 @@
+#include <aocpp/Startup.hpp>
+
+#include <cstdint>
+#include <stdexcept>
+
+auto Main(std::istream & in, std::ostream & out) -> void
+{
+  std::string line;
+  std::getline(in, line);
+
+  std::int64_t part1 = 0;
+  std::size_t part2 = 0;
+
+  for (std::size_t i = 0; i < line.size(); ++i)
+  {
+    switch (line[i]) {
+      case '(': part1++; break;
+      case ')': part1--; break;
+      default: throw std::runtime_error{"Invalid input character"};
+    }
+
+    if (part2 == 0 && part1 == -1)
+    {
+      part2 = i + 1;
+    }
+  }
+
+  if (part2 == 0)
+  {
+    throw std::runtime_error{"No part 2 solution"};
+  }
+
+  out << "Part 1: " << part1 << std::endl;
+  out << "Part 2: " << part2 << std::endl;
+}
diff --git a/2015/02.cpp b/2015/02.cpp
new file mode 100644
index 0000000..a929e88
--- /dev/null
+++ b/2015/02.cpp
@@ -0,0 +1,71 @@
+#include <aocpp/Startup.hpp>
+
+#include <boost/spirit/include/qi.hpp>
+
+#include <doctest.h>
+
+#include <algorithm>
+#include <array>
+#include <functional>
+#include <numeric>
+
+struct Box
+{
+  std::int64_t x;
+  std::int64_t y;
+  std::int64_t z;
+};
+
+auto Part1(Box const& box) -> std::int64_t
+{
+    std::array<std::int64_t, 3> sides {box.x * box.y, box.x * box.z, box.y * box.z};
+    std::partial_sort(begin(sides), begin(sides)+1, end(sides));
+    return 2 * std::reduce(begin(sides), end(sides)) + sides[0];
+}
+
+auto Part2(Box const& box) -> std::int64_t
+{
+  std::array<std::int64_t, 3> dims {box.x, box.y, box.z};
+  std::sort(begin(dims), end(dims));
+  return 2 * (dims[0] + dims[1]) + std::reduce(begin(dims), end(dims), 1, std::multiplies<>());
+}
+
+TEST_SUITE("documented examples") {
+
+TEST_CASE("part 1") {
+  REQUIRE(Part1({2,3,4}) == 58);
+  REQUIRE(Part1({1,1,10}) == 43);
+}
+
+TEST_CASE("part 2") {
+  REQUIRE(Part2({2,3,4}) == 34);
+  REQUIRE(Part2({1,1,10}) == 14);
+}
+
+}
+
+auto Main(std::istream & in, std::ostream & out) -> void
+{
+  std::int64_t part1 = 0;
+  std::int64_t part2 = 0;
+
+  std::string line;
+  while (std::getline(in, line)) {
+    namespace qi = boost::spirit::qi;
+    using p = qi::int_parser<std::int64_t>;
+    auto b = begin(line); // updated on successful parse
+    auto const e = end(line);
+
+    Box box;
+    if (not qi::parse(b, e, p{} >> 'x' >> p{} >> 'x' >> p{}, box.x, box.y, box.z) || b != e)
+    {
+      throw std::runtime_error{"Parse error"};
+    }
+
+    part1 += Part1(box);
+    part2 += Part2(box);
+  }
+
+  std::cout << "Part1: " << part1 << std::endl;
+  std::cout << "Part2: " << part2 << std::endl;
+}
diff --git a/2015/CMakeLists.txt b/2015/CMakeLists.txt
new file mode 100644
index 0000000..7275f05
--- /dev/null
+++ b/2015/CMakeLists.txt
@@ -0,0 +1,5 @@
+add_executable(2015_01 01.cpp)
+target_link_libraries(2015_01 aocpp)
+
+add_executable(2015_02 02.cpp)
+target_link_libraries(2015_02 aocpp)
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 94e5b4e..93bd855 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -26,6 +26,7 @@ add_subdirectory(dlx)
 add_subdirectory(knothash)
 add_subdirectory(zmod)
 add_subdirectory(intcode)
+add_subdirectory(2015)
 add_subdirectory(2016)
 add_subdirectory(2017)
 add_subdirectory(2018)
diff --git a/lib/include/aocpp/Counter.hpp b/lib/include/aocpp/Counter.hpp
index 0e3e87d..269eaf8 100644
--- a/lib/include/aocpp/Counter.hpp
+++ b/lib/include/aocpp/Counter.hpp
@@ -8,7 +8,7 @@ struct Counter
 {
   using difference_type = std::ptrdiff_t;
 
-  struct EmptyRef {
+  struct NoOpReference {
     template <typename T>
     auto operator=(T&&) const -> void {}
   };
@@ -31,14 +31,14 @@ struct Counter
     return n++;
   }
 
-  auto operator*() const -> EmptyRef
+  auto operator*() const -> NoOpReference
   {
     return {};
   }
 
   auto operator-(Counter rhs) const -> difference_type
   {
-    return static_cast<difference_type>(n) - static_cast<difference_type>(rhs);
+    return static_cast<difference_type>(n) - static_cast<difference_type>(rhs.n);
   }
 
   operator std::size_t() const
diff --git a/lib/include/aocpp/Parsing.hpp b/lib/include/aocpp/Parsing.hpp
index 223665a..1dd61ac 100644
--- a/lib/include/aocpp/Parsing.hpp
+++ b/lib/include/aocpp/Parsing.hpp
@@ -48,4 +48,4 @@ auto ParseGrammar_(G const& grammar, std::istream & in) -> typename G::start_typ
 
 }
 
-#endif
\ No newline at end of file
+#endif