Gather data

src/test/java/puzzle/MainTest.java

@@ -90,7 +90,7 @@ public class MainTest {
       // Initialize with #
       for (int r = 0; r < 3; r++) {
          for (int c = 0; c < 4; c++) {
-            grid.setCharAt(r, c, C_DASH);
+            grid.clear(r, c);
          }
       }