feat: solve day 17 part 2

src/main/java/com/adventofcode/flashk/day17/ChronospatialComputer.java

@@ -6,10 +6,8 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashMap;
-import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
-import java.util.Set;
 import java.util.StringJoiner;
 
 import java.util.regex.Pattern;
@@ -31,9 +29,9 @@ public class ChronospatialComputer {
     private List<ProgramState> programStates = new ArrayList<>();
 
     public ChronospatialComputer(List<String> inputs) {
-        a = Integer.parseInt(inputs.get(0).substring(12));
-        b = Integer.parseInt(inputs.get(1).substring(12));
-        c = Integer.parseInt(inputs.get(2).substring(12));
+        a = Long.parseLong(inputs.get(0).substring(12));
+        b = Long.parseLong(inputs.get(1).substring(12));
+        c = Long.parseLong(inputs.get(2).substring(12));
 
         expectedProgram = inputs.get(4).replace("Program: ", "");
         program = Arrays.stream(expectedProgram.split(",")).mapToInt(Integer::valueOf).toArray();
@@ -83,28 +81,6 @@ public long solveB() {
         // Parámetros recursivos:
         // - octal string: currentOctalDigit + octalDigit
 
-        /*
-        String result;
-
-
-        StringBuilder octalBuilder = new StringBuilder();
-        for(int digit = 0; digit < 16; digit++) {
-            String currentOctalDigit = octalBuilder.toString();
-            for(int octalDigit = 0; octalDigit < 8; octalDigit++) {
-
-                this.a = Long.parseLong(currentOctalDigit + octalDigit, 8);
-                this.b = 0;
-                this.c = 0;
-
-                result = solveA();
-
-                if(expectedProgram.endsWith(result)) {
-                    octalBuilder.append(octalDigit);
-                    break;
-                }
-            }
-
-        }*/
 
         return findRegistryA2(0, StringUtils.EMPTY, StringUtils.EMPTY);
 
@@ -113,10 +89,11 @@ public long solveB() {
 
     private long findRegistryA2(int digit, String currentOctalNumber, String output) {
 
+        /*
         if(digit == 11) {
             System.out.printf("oct: %s -> %s", currentOctalNumber, output);
             System.out.println();
-        }
+        }*/
 
         if(!expectedProgram.endsWith(output)) {
             return -1;

src/main/java/com/adventofcode/flashk/day17/Program.java

@@ -1,24 +1,47 @@
 package com.adventofcode.flashk.day17;
 
+import org.apache.commons.lang3.StringUtils;
+
+import java.util.Arrays;
 import java.util.List;
 import java.util.StringJoiner;
 
 public class Program {
 
-    public long a;
-    public long b;
-    public long c;
+    private long a;
+    private long b;
+    private long c;
+    private final String expectedProgram;
 
     public Program(List<String> inputs) {
         a = Integer.parseInt(inputs.get(0).substring(12));
         b = Integer.parseInt(inputs.get(1).substring(12));
         c = Integer.parseInt(inputs.get(2).substring(12));
+
+        expectedProgram = inputs.get(4).replace("Program: ", "");
+    }
+
+    public long solveB() {
+        return findRegistryA2(StringUtils.EMPTY, StringUtils.EMPTY);
+    }
+
+    public String execute() {
+        return run();
     }
 
     // Importante: este programa solo representa el programa de input.data
     // Cualquier otro programa tendría un set de instrucciones diferente.
-    public String execute() {
+    private String execute(long a) {
+        this.a = a;
+        this.b = 0;
+        this.c = 0;
+        return run();
+    }
+
+    private String run() {
+
         StringJoiner joiner = new StringJoiner(",");
+
         while(a != 0) {
             b = a % 8; // Se guarda en b 0-7, es decir, un número de 3 bits
             b = b ^ 3; // bitwise xor entre lo que valga b y "011"
@@ -29,7 +52,29 @@ public String execute() {
             joiner.add(String.valueOf(b % 8));
         }
 
-        System.out.println(joiner.toString());
         return joiner.toString();
     }
+
+    private long findRegistryA2(String currentOctalNumber, String output) {
+
+        if(!expectedProgram.endsWith(output)) {
+            return -1;
+        } else if(expectedProgram.equals(output)){
+            return Long.parseLong(currentOctalNumber, 8);
+        } else if(currentOctalNumber.length() == 16) {
+            return -1;
+        }
+
+        for(int octalDigit = 0; octalDigit < 8; octalDigit++) {
+            long numberA = Long.parseLong(currentOctalNumber + octalDigit, 8);
+
+            String partialOutput = execute(numberA);
+            long result = findRegistryA2(currentOctalNumber+octalDigit, partialOutput);
+            if(result != -1) {
+                return result;
+            }
+        }
+
+        return -1;
+    }
 }

src/test/java/com/adventofcode/flashk/day17/Day17Test.java

@@ -193,4 +193,29 @@ public void testSolvePart2Input() {
 
 	}
 
+	@Test
+	@Order(4)
+	@Tag(TestTag.PART_2)
+	@Tag(TestTag.INPUT)
+	@DisplayName(TestDisplayName.PART_2_INPUT)
+	@Disabled("[Disabled] Day 17 - testSolvePart2Input: Work in Progress")
+	public void part2InputWithProgramTest() {
+
+		// Read input file
+		List<String> inputs = Input.readStringLines(INPUT_FOLDER, TestFilename.INPUT_FILE);
+
+		Program program = new Program(inputs);
+
+		// Algunas consideraciones:
+		// La primera operación con los datos reales es 2,4
+		// Esto es, opcode 2, operator 4:
+		// - opcode 2 implica BST, esto es b = comboOperand % 8;
+		// - operator 4 implica que el valor de comboOperand va a ser el registro A
+		// Por lo tanto, valga lo que valga A, b adquirirá el valor de A % 8
+
+		// Help: https://www.reddit.com/r/adventofcode/comments/1hn01ke/2024_day_17_part_2_code_works_until_certain/
+		assertEquals(216549846240877L, program.solveB());
+
+	}
+
 }