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130 changes: 127 additions & 3 deletions
130
adventofcode/src/main/java/org/ck/adventofcode/year2016/Day24.java
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,18 +1,142 @@ | ||
| package org.ck.adventofcode.year2016; | ||
|
|
||
| import java.util.*; | ||
| import java.util.function.BiFunction; | ||
| import java.util.stream.Collectors; | ||
| import org.ck.adventofcode.util.AOCSolution; | ||
| import org.ck.codechallengelib.annotation.Solution; | ||
|
|
||
| @Solution( | ||
| id = 20162401, | ||
| name = "Day 24: Air Duct Spelunking", | ||
| url = "https://adventofcode.com/2016/day/24", | ||
| category = "2016") | ||
| @Solution( | ||
| id = 20162402, | ||
| name = "Day 24: Air Duct Spelunking - Part 2", | ||
| url = "https://adventofcode.com/2016/day/24", | ||
| category = "2016") | ||
| public class Day24 extends AOCSolution { | ||
| @Override | ||
| protected void runPartOne(final Scanner in) { | ||
| run(in); | ||
| run(in, (lastStep, distances) -> 0); | ||
| } | ||
|
|
||
| @Override | ||
| protected void runPartTwo(final Scanner in) { | ||
| run(in); | ||
| run(in, (lastStep, distances) -> distances.get('0').get(lastStep)); | ||
| } | ||
|
|
||
| private void run(final Scanner in) {} | ||
| private void run( | ||
| final Scanner in, | ||
| final BiFunction<Character, Map<Character, Map<Character, Integer>>, Integer> | ||
| lastStepLength) { | ||
| final List<char[]> grid = new ArrayList<>(); | ||
|
|
||
| while (in.hasNextLine()) { | ||
| grid.add(in.nextLine().toCharArray()); | ||
| } | ||
|
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| final List<Target> wanted = new ArrayList<>(); | ||
| for (int y = 0; y < grid.size(); ++y) { | ||
| for (int x = 0; x < grid.get(y).length; ++x) { | ||
| final char field = grid.get(y)[x]; | ||
|
|
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| if (field != '.' && field != '#') { | ||
| wanted.add(new Target(field, new Coordinate(x, y))); | ||
| } | ||
| } | ||
| } | ||
|
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| final Map<Character, Map<Character, Integer>> distances = new HashMap<>(); | ||
| for (int i = 0; i < wanted.size(); ++i) { | ||
| for (int j = i + 1; j < wanted.size(); ++j) { | ||
| final int steps = | ||
| findPathLength(grid, wanted.get(i).coordinate(), wanted.get(j).coordinate()); | ||
|
|
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| distances | ||
| .computeIfAbsent(wanted.get(i).name(), k -> new HashMap<>()) | ||
| .computeIfAbsent(wanted.get(j).name(), k -> steps); | ||
| distances | ||
| .computeIfAbsent(wanted.get(j).name(), k -> new HashMap<>()) | ||
| .computeIfAbsent(wanted.get(i).name(), k -> steps); | ||
| } | ||
| } | ||
|
|
||
| print( | ||
| getOverallDistance( | ||
| wanted.stream() | ||
| .map(Target::name) | ||
| .filter(target -> target != '0') | ||
| .collect(Collectors.toSet()), | ||
| distances, | ||
| '0', | ||
| lastStepLength)); | ||
| } | ||
|
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| private int getOverallDistance( | ||
| final Set<Character> remaining, | ||
| final Map<Character, Map<Character, Integer>> distances, | ||
| final char current, | ||
| final BiFunction<Character, Map<Character, Map<Character, Integer>>, Integer> | ||
| lastStepLength) { | ||
| if (remaining.isEmpty()) { | ||
| return lastStepLength.apply(current, distances); | ||
| } | ||
|
|
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| int distance = Integer.MAX_VALUE; | ||
|
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| for (final char next : remaining) { | ||
| distance = | ||
| Math.min( | ||
| distance, | ||
| getOverallDistance( | ||
| remaining.stream() | ||
| .filter(target -> target != next) | ||
| .collect(Collectors.toSet()), | ||
| distances, | ||
| next, | ||
| lastStepLength) | ||
| + distances.get(current).get(next)); | ||
| } | ||
|
|
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| return distance; | ||
| } | ||
|
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| private static int findPathLength( | ||
| final List<char[]> grid, final Coordinate start, final Coordinate end) { | ||
| final Queue<State> queue = new PriorityQueue<>(Comparator.comparingInt(State::steps)); | ||
| queue.add(new State(start, 0)); | ||
|
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| final Set<Coordinate> lookAheadCache = new HashSet<>(); | ||
|
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| while (!queue.isEmpty()) { | ||
| final State state = queue.poll(); | ||
| final Coordinate coordinate = state.coordinate(); | ||
|
|
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| if (coordinate.equals(end)) { | ||
| return state.steps(); | ||
| } | ||
|
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| for (final Coordinate next : | ||
| List.of( | ||
| new Coordinate(coordinate.x(), coordinate.y() - 1), | ||
| new Coordinate(coordinate.x(), coordinate.y() + 1), | ||
| new Coordinate(coordinate.x() - 1, coordinate.y()), | ||
| new Coordinate(coordinate.x() + 1, coordinate.y()))) { | ||
| if (grid.get(next.y())[next.x()] != '#' && !lookAheadCache.contains(next)) { | ||
| lookAheadCache.add(next); | ||
| queue.add(new State(next, state.steps() + 1)); | ||
| } | ||
| } | ||
| } | ||
|
|
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| return Integer.MAX_VALUE; | ||
| } | ||
|
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| private record Target(char name, Coordinate coordinate) {} | ||
|
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| private record Coordinate(int x, int y) {} | ||
|
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| private record State(Coordinate coordinate, int steps) {} | ||
| } |
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adventofcode/src/main/java/org/ck/adventofcode/year2016/day24/Part1.java
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adventofcode/src/main/java/org/ck/adventofcode/year2016/day24/Part2.java
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adventofcode/src/test/java/org/ck/adventofcode/year2016/Day24Test.java
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adventofcode/src/test/java/org/ck/adventofcode/year2016/day24/Part1Test.java
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adventofcode/src/test/java/org/ck/adventofcode/year2016/day24/Part2Test.java
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adventofcode/src/test/resources/org/ck/adventofcode/year2016/day24/01.result.txt
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| 0 | ||
| 412 |
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adventofcode/src/test/resources/org/ck/adventofcode/year2016/day24/02.result.txt
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| 0 | ||
| 664 |
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