diff --git a/2022/README.md b/2022/README.md
index ec0500ebfa8388518a3889114e06c74a46369c97..6c537cf04f9f76791579cb7f438ef53f559e6c39 100644
--- a/2022/README.md
+++ b/2022/README.md
@@ -322,7 +322,14 @@ That means that the clock cycle has advanced, but the accumulator hasn't updated
### Part 2
-...
+- Determine whether to illuminate the pixel for the current clock cycle
+- Determine the accumulator's value before the current instruction's result is latched in
+- Determine whether that value falls within the sprite's range
+
+### Refactoring
+
+Recognizing that we're now looking at many things that happen before the results are latched-in at the end of the cycle,
+I'm revisiting the signal strength code.
## Day 11
diff --git a/2022/src/main/java/edu/unl/cse/bohn/year2022/Day10.java b/2022/src/main/java/edu/unl/cse/bohn/year2022/Day10.java
index 016e48d1709381ae7a875c9560675739a97115a7..773c98655acaeb5f5fcd8b5e18535219c6abf42a 100644
--- a/2022/src/main/java/edu/unl/cse/bohn/year2022/Day10.java
+++ b/2022/src/main/java/edu/unl/cse/bohn/year2022/Day10.java
@@ -1,6 +1,7 @@
package edu.unl.cse.bohn.year2022;
import edu.unl.cse.bohn.Puzzle;
+import edu.unl.cse.bohn.year2022.computer.CathodeRayTube;
import edu.unl.cse.bohn.year2022.computer.Computer;
import java.util.List;
@@ -10,7 +11,10 @@ public class Day10 extends Puzzle {
public static final int INITIAL_CYCLE_FOR_MEASUREMENT = 20;
public static final int MEASUREMENT_STEP = 40;
+ public static final int SIZE_OF_DISPLAY = 240;
+ public static final int WIDTH_OF_DISPLAY = 40;
+ @SuppressWarnings("CommentedOutCode")
public Day10(boolean isProductionReady) {
super(isProductionReady);
// sampleData = """
@@ -20,11 +24,9 @@ public class Day10 extends Puzzle {
sampleData = muchLargerSampleData;
}
- private Computer computer = new Computer();
-
@Override
public long computePart1(List<String> data) {
- computer = new Computer();
+ Computer computer = new Computer();
computer.addInstructions(data);
int sumOfSignalStrengths = 0;
int i = 0;
@@ -38,8 +40,18 @@ public class Day10 extends Puzzle {
@Override
public long computePart2(List<String> data) {
- computer = new Computer();
+ Computer computer = new Computer();
computer.addInstructions(data);
+ CathodeRayTube display = new CathodeRayTube(SIZE_OF_DISPLAY, WIDTH_OF_DISPLAY, 3);
+ boolean moreToDisplay = true;
+ int pixel = 0;
+ while (moreToDisplay) {
+ moreToDisplay = computer.advanceOneCycle();
+ if (moreToDisplay) {
+ display.draw(computer.getAccumulatorDuringPreviousCycle());
+ }
+ }
+ System.out.println(display);
return 0;
}
diff --git a/2022/src/main/java/edu/unl/cse/bohn/year2022/computer/CathodeRayTube.java b/2022/src/main/java/edu/unl/cse/bohn/year2022/computer/CathodeRayTube.java
new file mode 100644
index 0000000000000000000000000000000000000000..915ba6ce41507d3d84fdb8962655c5133a99f9d2
--- /dev/null
+++ b/2022/src/main/java/edu/unl/cse/bohn/year2022/computer/CathodeRayTube.java
@@ -0,0 +1,51 @@
+package edu.unl.cse.bohn.year2022.computer;
+
+import java.util.Arrays;
+
+public class CathodeRayTube {
+ private final Boolean[][] pixels;
+ private final int pixelsPerRow;
+ private final int spriteMargin;
+ private int row;
+ private int column;
+
+ public CathodeRayTube(int numberOfPixels, int pixelsPerRow, int spriteWidth) {
+ this.pixelsPerRow = pixelsPerRow;
+ pixels = new Boolean[numberOfPixels / pixelsPerRow][pixelsPerRow];
+ Arrays.stream(pixels).forEach(row -> Arrays.fill(row, null));
+ this.spriteMargin = (spriteWidth - 1) / 2;
+ row = 0;
+ column = 0;
+ }
+
+ @SuppressWarnings("UnusedReturnValue")
+ public boolean draw(int targetPixel) {
+ if (column == pixelsPerRow) {
+ row++;
+ column = 0;
+ if (row == pixels.length) {
+ row = 0;
+ }
+ }
+ pixels[row][column] = (Math.abs(targetPixel - column) <= spriteMargin);
+ boolean illuminated = pixels[row][column];
+ column++;
+ return illuminated;
+ }
+
+ @Override
+ public String toString() {
+ StringBuilder stringBuilder = new StringBuilder(pixels.length * (pixelsPerRow + 1));
+ for (Boolean[] row : pixels) {
+ stringBuilder.append(System.lineSeparator());
+ for (Boolean pixel : row) {
+ if (pixel == null) {
+ stringBuilder.append('?');
+ } else {
+ stringBuilder.append(pixel ? '#' : ' ');
+ }
+ }
+ }
+ return stringBuilder.toString();
+ }
+}
diff --git a/2022/src/main/java/edu/unl/cse/bohn/year2022/computer/Computer.java b/2022/src/main/java/edu/unl/cse/bohn/year2022/computer/Computer.java
index 84775523cdda278e8049cad45fd8b9d7426f03a5..526d5c44fcfd766061048e19ede0fa9a904a787c 100644
--- a/2022/src/main/java/edu/unl/cse/bohn/year2022/computer/Computer.java
+++ b/2022/src/main/java/edu/unl/cse/bohn/year2022/computer/Computer.java
@@ -8,13 +8,13 @@ public class Computer {
private final Context context;
private final Deque<Instruction> instructions;
private int reportedCycleNumber;
- private int signalStrength;
+ private int accumulatorValueBeforeCurrentCycle;
public Computer() {
context = new Context();
instructions = new LinkedList<>();
reportedCycleNumber = 0;
- signalStrength = 0;
+ accumulatorValueBeforeCurrentCycle = 0;
}
public void addInstruction(String instruction) {
@@ -45,12 +45,12 @@ public class Computer {
return reportedCycleNumber;
}
- private void setSignalStrengthForNextCycle() {
- signalStrength = (getCycle() + 1) * context.rX;
+ public int getAccumulatorDuringPreviousCycle() {
+ return accumulatorValueBeforeCurrentCycle;
}
public int getSignalStrengthDuringPreviousCycle() {
- return signalStrength;
+ return getAccumulatorDuringPreviousCycle() * getCycle();
}
/**
@@ -69,22 +69,22 @@ public class Computer {
+ reportedCycleNumber + " and the requested cycle is " + cycleNumber + ".");
}
while (!instructionsAreAvailable() && reportedCycleNumber < cycleNumber) {
+ accumulatorValueBeforeCurrentCycle = context.rX;
if (context.clockCycle + instructions.getFirst().getDuration() > cycleNumber) {
- // if executing the next instruction would advance the clock too far
- reportedCycleNumber = cycleNumber - 1;
- setSignalStrengthForNextCycle();
- reportedCycleNumber++;
+ reportedCycleNumber = cycleNumber;
} else {
Instruction nextInstruction = instructions.removeFirst();
- reportedCycleNumber = context.clockCycle + nextInstruction.getDuration() - 1;
- setSignalStrengthForNextCycle();
nextInstruction.execute(context);
- reportedCycleNumber++;
+ reportedCycleNumber = context.clockCycle;
}
}
return reportedCycleNumber == cycleNumber;
}
+ public boolean advanceOneCycle() {
+ return advanceToCycle(getCycle() + 1);
+ }
+
public String toString() {
return "reported cycle: " + getCycle() + " (actual " + context.clockCycle + ")" + "\tRX: " + context.rX + "\t"
+ (instructionsAreAvailable() ? "--idle--" : (context.clockCycle == getCycle() ? " next" : "current")