day03 for AoC 2023 (part 2)

Took 11 minutes

Author: albertominetti

src/main/java/aminetti/adventofcode2024/day03/Day03.java

@@ -38,7 +38,34 @@ public long solvePart1() {
     }
 
     public long solvePart2() {
+        Pattern p = Pattern.compile("(?:mul\\((\\d{1,3}),(\\d{1,3})\\))|(?:do\\(\\))|(?:don't\\(\\))");
 
-        return 0;
+        long sum = 0L;
+        boolean mulEnabled = true;
+        for (String s : input) {
+            Matcher matcher = p.matcher(s);
+
+            while (matcher.find()) {
+                String fullMatch = matcher.group(0);
+                if (fullMatch.startsWith("mul")) {
+                    if (mulEnabled) {
+                        LOGGER.info("Executing {}", fullMatch);
+                        Long a = Long.valueOf(matcher.group(1));
+                        Long b = Long.valueOf(matcher.group(2));
+                        sum += a * b;
+                    } else {
+                        LOGGER.info("Skipping {}", fullMatch);
+                    }
+                } else if (fullMatch.startsWith("do()")) {
+                    LOGGER.info("Enabling {}", fullMatch);
+                    mulEnabled = true;
+                } else if (fullMatch.startsWith("don't()")) {
+                    LOGGER.info("Disabling {}", fullMatch);
+                    mulEnabled = false;
+                }
+            }
+        }
+
+        return sum;
     }
 }

src/test/java/aminetti/adventofcode2024/day03/Day03Test.java

@@ -52,21 +52,21 @@ void actualInputPart2() throws IOException {
         long l = solver.solvePart2();
 
         // then
-        assertThat(l, is(0L));
+        assertThat(l, is(80570939L));
     }
 
     @Test
     void testInputPart2() throws IOException {
         // given
-        List<String> input = readLines(resourceToString("/day03/day03_input_test.txt", UTF_8));
+        List<String> input = readLines(resourceToString("/day03/day03_input_test2.txt", UTF_8));
 
         // when
         Day03 solver = new Day03();
         solver.parseInput(input);
         long l = solver.solvePart2();
 
         // then
-        assertThat(l, is(0L));
+        assertThat(l, is(48L));
     }
 
 

src/test/resources/day03/day03_input_test2.txt

@@ -0,0 +1 @@
+xmul(2,4)&mul[3,7]!^don't()_mul(5,5)+mul(32,64](mul(11,8)undo()?mul(8,5))