Add solution for "Day 21: Keypad Conundrum", part 2

src/extra/KeypadRobot.cpp

@@ -22,8 +22,11 @@ KeypadRobot::KeypadRobot(const std::map<char, Point2>&& keypad, const Point2&& f
 {
 }
 
-std::string KeypadRobot::calcInputKeys(const std::string& targetOutputKeys) const
+KeypadPatternTransformation KeypadRobot::calcTransformation(const std::string& targetOutputKeys) const
 {
+    KeypadPatternTransformation result{};
+    result.accumulatedLengths.push_back(targetOutputKeys.size());
+
     std::ostringstream stream{};
     Point2 position{ 0, 0 };
     for (const char c : targetOutputKeys)
@@ -32,37 +35,44 @@ std::string KeypadRobot::calcInputKeys(const std::string& targetOutputKeys) cons
 
         // This specific order of robot arm movements aims to reduce resulting combinations of 'A' and '<' for the
         // second robot, which expand to more key presses starting with the third robot.
-        bool horizontalFirst{ (next.x < position.x && !(next.x == forbidden_.x && position.y == forbidden_.y)) ||
-            (position.x == forbidden_.x && next.y == forbidden_.y) };
+        bool horizontalFirst{ (next.x < position.x && !isForbidden(next.x, position.y)) ||
+            isForbidden(position.x, next.y) };
         if (horizontalFirst)
         {
-            move(stream, next.x - position.x, '>', '<');
+            move(stream, next.x - position.x, '>', '<', result.nDuplicates);
         }
-        move(stream, next.y - position.y, 'v', '^');
+        move(stream, next.y - position.y, 'v', '^', result.nDuplicates);
         if (!horizontalFirst)
         {
-            move(stream, next.x - position.x, '>', '<');
+            move(stream, next.x - position.x, '>', '<', result.nDuplicates);
         }
         stream << 'A';
+
+        result.parts.push_back(stream.str());
+        stream.str("");
+
         position = next;
     }
-    return stream.str();
+
+    return result;
 }
 
-void KeypadRobot::move(std::ostringstream& stream, const int delta, const char positive, const char negative) const
+void KeypadRobot::move(std::ostringstream& stream, const int delta, const char positive, const char negative,
+    int& nDuplicates) const
 {
     if (delta > 0)
     {
-        for (int i{ 0 }; i < delta; i++)
-        {
-            stream << positive;
-        }
+        stream << positive;
+        nDuplicates += delta - 1;
     }
-    else
+    else if (delta < 0)
     {
-        for (int i{ 0 }; i < -delta; i++)
-        {
-            stream << negative;
-        }
+        stream << negative;
+        nDuplicates -= delta + 1;
     }
 }
+
+bool KeypadRobot::isForbidden(const int x, const int y) const
+{
+    return x == forbidden_.x && y == forbidden_.y;
+}