aoc 2017 day 9

Author: TheCK

adventofcode/README.md

@@ -406,7 +406,7 @@
 [20162402tests]: src/test/java/org/ck/adventofcode/year2016/Day24Test.java
 [20162501tests]: src/test/java/org/ck/adventofcode/year2016/Day25Test.java
 
-# 2017 (16/16)
+# 2017 (18/18)
 
 |        # | Name                                                                | Solution                             | Test                              |
 |---------:|---------------------------------------------------------------------|:------------------------------------:|:---------------------------------:|
@@ -426,6 +426,8 @@
 | 20170702 | [Day 7: Recursive Circus - Part 2][20170702]                        | ✅[💾][20170702solution] | ✅[💾][20170702tests] |
 | 20170801 | [Day 8: I Heard You Like Registers][20170801]                       | ✅[💾][20170801solution] | ✅[💾][20170801tests] |
 | 20170802 | [Day 8: I Heard You Like Registers - Part 2][20170802]              | ✅[💾][20170802solution] | ✅[💾][20170802tests] |
+| 20170901 | [Day 9: Stream Processing][20170901]                                | ✅[💾][20170901solution] | ✅[💾][20170901tests] |
+| 20170902 | [Day 9: Stream Processing - Part 2][20170902]                       | ✅[💾][20170902solution] | ✅[💾][20170902tests] |
 
 [20170101]: https://adventofcode.com/2017/day/1
 [20170102]: https://adventofcode.com/2017/day/1#part2
@@ -443,6 +445,8 @@
 [20170702]: https://adventofcode.com/2017/day/7#part2
 [20170801]: https://adventofcode.com/2017/day/8
 [20170802]: https://adventofcode.com/2017/day/8#part2
+[20170901]: https://adventofcode.com/2017/day/9
+[20170902]: https://adventofcode.com/2017/day/9#part2
 
 [20170101solution]: src/main/java/org/ck/adventofcode/year2017/Day01.java
 [20170102solution]: src/main/java/org/ck/adventofcode/year2017/Day01.java
@@ -460,6 +464,8 @@
 [20170702solution]: src/main/java/org/ck/adventofcode/year2017/Day07.java
 [20170801solution]: src/main/java/org/ck/adventofcode/year2017/Day08.java
 [20170802solution]: src/main/java/org/ck/adventofcode/year2017/Day08.java
+[20170901solution]: src/main/java/org/ck/adventofcode/year2017/Day09.java
+[20170902solution]: src/main/java/org/ck/adventofcode/year2017/Day09.java
 
 [20170101tests]: src/test/java/org/ck/adventofcode/year2017/Day01Test.java
 [20170102tests]: src/test/java/org/ck/adventofcode/year2017/Day01Test.java
@@ -477,6 +483,8 @@
 [20170702tests]: src/test/java/org/ck/adventofcode/year2017/Day07Test.java
 [20170801tests]: src/test/java/org/ck/adventofcode/year2017/Day08Test.java
 [20170802tests]: src/test/java/org/ck/adventofcode/year2017/Day08Test.java
+[20170901tests]: src/test/java/org/ck/adventofcode/year2017/Day09Test.java
+[20170902tests]: src/test/java/org/ck/adventofcode/year2017/Day09Test.java
 
 # 2019 (29/30)
 

adventofcode/src/main/java/org/ck/adventofcode/year2017/Day09.java

@@ -0,0 +1,91 @@
+package org.ck.adventofcode.year2017;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Scanner;
+import java.util.function.ToIntFunction;
+import org.ck.adventofcode.util.AOCSolution;
+import org.ck.codechallengelib.annotation.Solution;
+
+@Solution(
+    id = 20170901,
+    name = "Day 9: Stream Processing",
+    url = "https://adventofcode.com/2017/day/9",
+    category = "2017")
+@Solution(
+    id = 20170902,
+    name = "Day 9: Stream Processing - Part 2",
+    url = "https://adventofcode.com/2017/day/9#part2",
+    category = "2017")
+public class Day09 extends AOCSolution {
+  @Override
+  protected void runPartOne(final Scanner in) {
+    run(in, result -> count(result.result(), 1));
+  }
+
+  @Override
+  protected void runPartTwo(final Scanner in) {
+    run(in, ParseResult::garbageCount);
+  }
+
+  private void run(final Scanner in, final ToIntFunction<ParseResult> getResult) {
+    final String line = in.nextLine();
+
+    print(getResult.applyAsInt(parse(line, 1)));
+  }
+
+  private int count(final List<?> result, final int value) {
+    int count = value;
+
+    for (Object o : result) {
+      if (o instanceof List<?> list) {
+        count += count(list, value + 1);
+      }
+    }
+
+    return count;
+  }
+
+  private static ParseResult parse(final String line, final int start) {
+    final List<Object> result = new ArrayList<>();
+    int index = start;
+    int garbageCount = 0;
+
+    while (line.charAt(index) != '}') {
+      if (line.charAt(index) == '{') {
+        final ParseResult parseResult = parse(line, index + 1);
+
+        result.add(parseResult.result());
+        garbageCount += parseResult.garbageCount();
+        index = parseResult.newIndex() + 1;
+      } else if (line.charAt(index) == ',') {
+        ++index;
+      } else if (line.charAt(index) == '<') {
+        final ParseResult parseResult = parseGarbage(line, index + 1);
+
+        garbageCount += parseResult.garbageCount();
+        index = parseResult.newIndex() + 1;
+      }
+    }
+
+    return new ParseResult(result, index, garbageCount);
+  }
+
+  private static ParseResult parseGarbage(final String line, final int start) {
+    int index = start;
+    int garbageCount = 0;
+
+    while (line.charAt(index) != '>') {
+      if (line.charAt(index) == '!') {
+        index += 2;
+      } else {
+        ++garbageCount;
+        ++index;
+      }
+    }
+
+    return new ParseResult(null, index, garbageCount);
+  }
+
+  private record ParseResult(List<Object> result, int newIndex, int garbageCount) {}
+}

adventofcode/src/test/java/org/ck/adventofcode/year2017/Day09Test.java

@@ -0,0 +1,19 @@
+package org.ck.adventofcode.year2017;
+
+import org.ck.adventofcode.util.BaseAOCTest;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+
+class Day09Test extends BaseAOCTest {
+  @ParameterizedTest
+  @ValueSource(strings = {"01", "01a", "01b", "01c", "01d", "01e", "01f", "01g", "01h"})
+  void testOne(String name) throws Exception {
+    runTest(new Day09()::partOne, "day09/%s".formatted(name));
+  }
+
+  @ParameterizedTest
+  @ValueSource(strings = {"02", "02a", "02b", "02c", "02d", "02e", "02f", "02g", "02h"})
+  void testTwo(String name) throws Exception {
+    runTest(new Day09()::partTwo, "day09/%s".formatted(name));
+  }
+}

adventofcode/src/test/resources/org/ck/adventofcode/year2017/day09/01.result.txt

@@ -0,0 +1 @@
+12505

adventofcode/src/test/resources/org/ck/adventofcode/year2017/day09/01.txt

@@ -0,0 +1 @@
+1

adventofcode/src/test/resources/org/ck/adventofcode/year2017/day09/01a.result.txt

@@ -0,0 +1 @@
+{}

adventofcode/src/test/resources/org/ck/adventofcode/year2017/day09/01a.txt

@@ -0,0 +1 @@
+6

adventofcode/src/test/resources/org/ck/adventofcode/year2017/day09/01b.result.txt

@@ -0,0 +1 @@
+{{{}}}

adventofcode/src/test/resources/org/ck/adventofcode/year2017/day09/01b.txt

@@ -0,0 +1 @@
+5