Added solution for 2016 day 2

nycofox · nycofox · commit a73b2f6994b6 · 2024-10-25T09:50:15.000+02:00
diff --git a/src/AdventSolutions/Year2016/Day2/Solution2016Day2.php b/src/AdventSolutions/Year2016/Day2/Solution2016Day2.php
@@ -8,42 +8,34 @@ class Solution2016Day2 extends AbstractSolution
 {
     public function solvePart1($input): string
     {
-        $startposition = [1, 1];
-
         $code = '';
-
-        // for each input line, move according to each letter
+        $position = [1, 1]; // Start at '5' on a 3x3 grid
 
         foreach ($input as $line) {
-            $position = $startposition;
             $instructions = str_split($line);
             foreach ($instructions as $instruction) {
-                switch ($instruction) {
-                    case 'U':
-                        $position = $this->moveUp($position);
-                        break;
-                    case 'D':
-                        $position = $this->moveDown($position);
-                        break;
-                    case 'L':
-                        $position = $this->moveLeft($position);
-                        break;
-                    case 'R':
-                        $position = $this->moveRight($position);
-                        break;
-                }
+                $position = $this->move($position, $instruction, $this->keypad());
             }
             $code .= $this->keypad()[$position[1]][$position[0]];
         }
-        
-        return "The code is: <info>$code</info>";
+
+        return "The code for Part 1 is: <info>$code</info>";
     }
 
     public function solvePart2($input): string
     {
-        // Implement the logic for solving part 2 here
-        
-        return "Part 2 not yet implemented!";
+        $code = '';
+        $position = [0, 2]; // Start at '5' on the Part 2 keypad layout
+
+        foreach ($input as $line) {
+            $instructions = str_split($line);
+            foreach ($instructions as $instruction) {
+                $position = $this->move($position, $instruction, $this->keypad2());
+            }
+            $code .= $this->keypad2()[$position[1]][$position[0]];
+        }
+
+        return "The code for Part 2 is: <info>$code</info>";
     }
 
     private function keypad(): array
@@ -55,27 +47,42 @@ private function keypad(): array
         ];
     }
 
-    private function moveUp($position): array
+    private function keypad2(): array
     {
-        $position[1] = max(0, $position[1] - 1);
-        return $position;
+        return [
+            [null, null, 1, null, null],
+            [null, 2, 3, 4, null],
+            [5, 6, 7, 8, 9],
+            [null, 'A', 'B', 'C', null],
+            [null, null, 'D', null, null],
+        ];
     }
 
-    private function moveDown($position): array
+    private function move(array $position, string $direction, array $keypad): array
     {
-        $position[1] = min(2, $position[1] + 1);
-        return $position;
-    }
+        $x = $position[0];
+        $y = $position[1];
 
-    private function moveLeft($position): array
-    {
-        $position[0] = max(0, $position[0] - 1);
-        return $position;
-    }
+        switch ($direction) {
+            case 'U':
+                $y = max(0, $y - 1);
+                break;
+            case 'D':
+                $y = min(count($keypad) - 1, $y + 1);
+                break;
+            case 'L':
+                $x = max(0, $x - 1);
+                break;
+            case 'R':
+                $x = min(count($keypad[$y]) - 1, $x + 1);
+                break;
+        }
+
+        // Only update position if within bounds of the keypad layout
+        if ($keypad[$y][$x] !== null) {
+            $position = [$x, $y];
+        }
 
-    private function moveRight($position): array
-    {
-        $position[0] = min(2, $position[0] + 1);
         return $position;
     }
-}
+}
