Add solution for 2016 Day 9

res/2016/day09/test_input.txt

@@ -0,0 +1 @@
+X(8x2)(3x3)ABCY

src/2016/Day09.cpp

@@ -2,30 +2,74 @@
 
 namespace y2016::day09
 {
-  REGISTER_DAY(2016, Day09, std::vector<int>, int);
+  REGISTER_DAY(2016, Day09, std::string, uint64_t);
 
-  REGISTER_TEST_EXAMPLE(2016, Day09, ExampleInput, 1, 0);
+  REGISTER_TEST_EXAMPLE(2016, Day09, ExampleInput, 1, 18);
-  REGISTER_TEST(2016, Day09, Input, 1, 0);
+  REGISTER_TEST(2016, Day09, Input, 1, 99145);
-  REGISTER_TEST_EXAMPLE(2016, Day09, ExampleInput, 2, 0);
+  REGISTER_TEST_EXAMPLE(2016, Day09, ExampleInput, 2, 20);
-  REGISTER_TEST(2016, Day09, Input, 2, 0);
+  REGISTER_TEST(2016, Day09, Input, 2, 10943094568);
 
   READ_INPUT(input)
   {
-    std::vector<int> vec;
     std::string str;
-    while (getline(input, str))
+    getline(input, str);
-    {
+    return str;
   }
-    return vec;
+
+  std::pair<int, int> GetMarker(const char* str)
+  {
+    char* end;
+    int length = std::strtol(str, &end, 10);
+    int repeat = std::strtol(end + 1, nullptr, 10);
+    return {length, repeat};
+  }
+
+  uint64_t GetLength(const char* str, size_t strLength)
+  {
+    size_t i = 0;
+    uint64_t count = 0;
+    while (i < strLength)
+    {
+      if (str[i] == '(')
+      {
+        size_t close = std::strstr(str + i, ")") - str;
+        auto [length, repeat] = GetMarker(str + i + 1);
+        count += GetLength(str + close + 1, length) * repeat;
+        i = close + 1 + length;
+      }
+      else
+      {
+        count++;
+        i++;
+      }
+    }
+    return count;
   }
 
   OUTPUT1(input)
   {
-    return 0;
+    uint64_t count = 0;
+    size_t i = 0;
+    while (i < input.size())
+    {
+      if (input[i] == '(')
+      {
+        size_t close = input.find(')', i);
+        auto [length, repeat] = GetMarker(input.c_str() + i + 1);
+        count += length * repeat;
+        i = close + 1 + length;
+      }
+      else
+      {
+        count++;
+        i++;
+      }
+    }
+    return count;
   }
 
   OUTPUT2(input)
   {
-    return 0;
+    return GetLength(input.c_str(), input.size());
   }
 }