Add solution for 2016 Day 20

src/2016/Day20.cpp

@@ -2,30 +2,60 @@
 
 namespace y2016::day20
 {
-  REGISTER_DAY(2016, Day20, std::vector<int>, int);
+  using Input = std::vector<std::pair<uint64_t, uint64_t>>;
+  REGISTER_DAY(2016, Day20, Input, uint32_t);
 
-  REGISTER_TEST_EXAMPLE(2016, Day20, ExampleInput, 1, 0);
-  REGISTER_TEST(2016, Day20, Input, 1, 0);
-  REGISTER_TEST_EXAMPLE(2016, Day20, ExampleInput, 2, 0);
-  REGISTER_TEST(2016, Day20, Input, 2, 0);
+  REGISTER_TEST_EXAMPLE(2016, Day20, ExampleInput, 1, 3);
+  REGISTER_TEST(2016, Day20, Input, 1, 19449262);
+  REGISTER_TEST_EXAMPLE(2016, Day20, ExampleInput, 2, 2);
+  REGISTER_TEST(2016, Day20, Input, 2, 119);
 
   READ_INPUT(input)
   {
-    std::vector<int> vec;
+    std::vector<std::pair<uint64_t, uint64_t>> vec;
     std::string str;
     while (getline(input, str))
     {
+      std::pair<uint32_t, uint32_t> pair;
+      std::stringstream ss{str};
+      ss >> pair.first >> "-" >> pair.second;
+      vec.emplace_back(pair);
     }
+    std::sort(vec.begin(), vec.end());
     return vec;
   }
 
   OUTPUT1(input)
   {
+    if (input.front().first != 0)
+      return 0;
+
+    for (int i = 0; i < input.size(); i++)
+    {
+      if (input[i].second + 1 < input[i + 1].first)
+        return input[i].second + 1;
+    }
     return 0;
   }
 
   OUTPUT2(input)
   {
-    return 0;
+    uint64_t allowed = input.front().first;
+    uint64_t currentMax = input.front().second;
+    for (int i = 1; i < input.size(); i++)
+    {
+      if (currentMax < input[i].first - 1)
+      {
+        allowed += input[i].first - currentMax - 1;
+        currentMax = input[i].second;
+      }
+      else
+      {
+        currentMax = std::max(currentMax, input[i].second);
+      }
+    }
+    uint32_t max = isExample ? 9 : std::numeric_limits<uint32_t>::max();
+    allowed += max - currentMax;
+    return allowed;
   }
 }