121 lines
3.8 KiB
C#
121 lines
3.8 KiB
C#
using System.Collections.Generic;
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using System.IO;
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using System.Linq;
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using AdvenOfCode.Contracts;
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using Range = (long from, long to);
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namespace AoC_2025;
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public class Day05 : IPuzzleSolver<long>
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{
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private (List<string> freshIdRanges, List<string> ids) ParsePuzzleInput(string path)
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{
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var puzzleInput = File.ReadAllLines(path)
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.Select(line => line.Trim())
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.ToList();
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var middle = puzzleInput.IndexOf("");
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var freshIdRanges = puzzleInput[..middle];
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var ids = puzzleInput[(middle + 1)..];
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return (freshIdRanges, ids);
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}
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public long SolvePart1(string pathToPuzzleInput)
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{
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var database = ParsePuzzleInput(pathToPuzzleInput);
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var freshIdRanges = ParseRanges(database.freshIdRanges);
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var ids = ParseIds(database.ids);
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var freshIds = FilterFreshIds(ids, freshIdRanges);
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return freshIds.Count();
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}
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public long SolvePart2(string pathToPuzzleInput)
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{
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var database = ParsePuzzleInput(pathToPuzzleInput);
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var freshIdRanges = ParseRanges(database.freshIdRanges);
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var sumIds = SumIdsInRanges(freshIdRanges);
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return sumIds;
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}
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public long SolvePart2Again(string pathToPuzzleInput)
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{
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var database = ParsePuzzleInput(pathToPuzzleInput);
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var freshIdRanges = ParseRanges(database.freshIdRanges);
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var combinedRanges = CombineOverlappingRanges(freshIdRanges);
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var countIdsInRanges = CountIdsInRanges(combinedRanges);
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var sumIds = countIdsInRanges.Sum();
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return sumIds;
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}
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private IEnumerable<long> ParseIds(List<string> ids)
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{
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var parsedIds = ids.Select(id => long.Parse(id));
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return parsedIds;
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}
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private Range[] ParseRanges(IEnumerable<string> ranges)
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{
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return ranges.Select(range =>
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{
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var split = range.Split('-', StringSplitOptions.RemoveEmptyEntries);
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return (long.Parse(split[0]), long.Parse(split[1]));
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})
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.OrderBy(range => range.Item1)
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.ThenBy(range => range.Item2)
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.ToArray();
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}
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private IEnumerable<long> FilterFreshIds(IEnumerable<long> ids, Range[] freshIdRanges)
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{
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var freshIds = ids.Where(id => IsIdInRanges(id, freshIdRanges));
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return freshIds;
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}
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private bool IsIdInRanges(long id, IEnumerable<Range> ranges)
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{
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return ranges.Any(range => IsIdInRange(id, range));
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}
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private bool IsIdInRange(long id, Range range)
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{
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return range.from <= id && range.to >= id;
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}
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private long SumIdsInRanges(IEnumerable<Range> ranges)
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{
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var sumFreshIds = 0L;
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var highestSeenId = -1L;
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foreach (var range in ranges)
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{
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var lowestNewId = Math.Max(highestSeenId + 1, range.from);
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highestSeenId = Math.Max(highestSeenId, range.to);
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sumFreshIds += Math.Max(0, highestSeenId - lowestNewId + 1);
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}
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return sumFreshIds;
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}
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private List<Range> CombineOverlappingRanges(Range[] ranges)
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{
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var optimizedRanges = new List<Range>(ranges.Length) { ranges[0] };
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foreach (var range in ranges)
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{
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var lastRange = optimizedRanges[^1];
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if (range.from > lastRange.to)
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{
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optimizedRanges.Add(range);
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}
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else if (IsIdInRange(range.from, lastRange) && ! IsIdInRange(range.to, lastRange))
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{
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optimizedRanges[^1] = (lastRange.from, range.to);
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}
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}
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return optimizedRanges;
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}
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private static IEnumerable<long> CountIdsInRanges(IEnumerable<Range> combinedRanges)
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{
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var countIdsInRanges = combinedRanges.Select(range => range.to - range.from + 1);
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return countIdsInRanges;
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}
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} |