Add solution for 2016 Day 13

res/2016/day13/test_input.txt

@@ -0,0 +1 @@
+10

src/2016/Day13.cpp

@@ -2,30 +2,102 @@
 
 namespace y2016::day13
 {
-  REGISTER_DAY(2016, Day13, std::vector<int>, int);
+  REGISTER_DAY(2016, Day13, int, int);
 
-  REGISTER_TEST_EXAMPLE(2016, Day13, ExampleInput, 1, 0);
-  REGISTER_TEST(2016, Day13, Input, 1, 0);
-  REGISTER_TEST_EXAMPLE(2016, Day13, ExampleInput, 2, 0);
-  REGISTER_TEST(2016, Day13, Input, 2, 0);
+  REGISTER_TEST_EXAMPLE(2016, Day13, ExampleInput, 1, 11);
+  REGISTER_TEST(2016, Day13, Input, 1, 82);
+  REGISTER_TEST_EXAMPLE(2016, Day13, ExampleInput, 2, 151);
+  REGISTER_TEST(2016, Day13, Input, 2, 138);
 
   READ_INPUT(input)
   {
-    std::vector<int> vec;
-    std::string str;
-    while (getline(input, str))
+    int i;
+    input >> i;
+    return i;
+  }
+
+  bool IsWall(int x, int y, int number)
+  {
+    int i = x * x + 3 * x + 2 * x * y + y + y * y;
+    i += number;
+    std::string str = std::bitset<32>(i).to_string();
+    // std::cout << str << ": " << std::count(str.begin(), str.end(), '1') % 2 << std::endl;
+    return std::count(str.begin(), str.end(), '1') % 2 != 0;
+  }
+
+  struct State
+  {
+    int x;
+    int y;
+
+    bool operator==(const State& state) const
     {
+      return x == state.x && y == state.y;
     }
-    return vec;
+
+    bool operator<(const State& state) const
+    {
+      if (x != state.x)
+        return x < state.x;
+      return y < state.y;
+    }
+
+    friend std::ostream& operator<<(std::ostream& os, const State& state)
+    {
+      return os << "(" << state.x << ", " << state.y << ")";
+    }
+  };
+
+  std::vector<std::pair<int, State>> Branch(int input, const State& state)
+  {
+    std::vector<std::pair<int, State>> branches;
+    if (state.x > 0 && !IsWall(state.x - 1, state.y, input))
+      branches.emplace_back(1, State{state.x - 1, state.y});
+    if (state.y > 0 && !IsWall(state.x, state.y - 1, input))
+      branches.emplace_back(1, State{state.x, state.y - 1});
+    if (!IsWall(state.x + 1, state.y, input))
+      branches.emplace_back(1, State{state.x + 1, state.y});
+    if (!IsWall(state.x, state.y + 1, input))
+      branches.emplace_back(1, State{state.x, state.y + 1});
+    return branches;
+  }
+
+  bool Goal(int input, const State& state)
+  {
+    if (input == 10)
+      return state == State{7, 4};
+    else
+      return state == State{31, 39};
   }
 
   OUTPUT1(input)
   {
-    return 0;
+    State state{1, 1};
+    return Helper::Dijkstras(input, state, Branch, Goal);
   }
 
   OUTPUT2(input)
   {
-    return 0;
+    std::queue<std::pair<int, State>> queue{};
+    queue.emplace(0, State{1, 1});
+    std::set<State> visited;
+    while (!queue.empty())
+    {
+      std::pair<int, State> state = queue.front();
+      queue.pop();
+
+      std::vector<std::pair<int, State>> branches = Branch(input, state.second);
+      for (const auto& branch : branches)
+      {
+        if (!visited.emplace(branch.second).second)
+          continue;
+
+        if (state.first >= 49)
+          continue;
+        else
+          queue.emplace(state.first + 1, branch.second);
+      }
+    }
+    return visited.size();
   }
 }