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AdventOfCode 2023 Day05 Part2, Optimized using range mapping clipping

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This commit is contained in:
Valeriano A.R.
2023-12-07 21:10:43 +01:00
parent 55487f7b61
commit 3e8fa75253
2 changed files with 346 additions and 18 deletions
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174
AdventOfCode2023/Day05.cs
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@@ -135,19 +135,22 @@ public class Day05 : IDay
{
LinesReader reader = new(inputs);
Almanac? almanac = Almanac.Parse(reader);
long minLocation = long.MaxValue;
int i = 0;
List<AlmanacRangeMapping> ranges = new();
while (almanac?.Seeds.Count > i)
{
long seed = almanac?.Seeds[i] ?? 0;
long seedLen = almanac?.Seeds[i + 1] ?? 0;
for (long j = 0; j < seedLen; j++)
{
long currentSeed = almanac?.ApplyMapping(seed + j) ?? 0;
if (currentSeed < minLocation) { minLocation = currentSeed; }
}
long seed = almanac.Seeds[i];
long seedLen = almanac.Seeds[i + 1];
AlmanacRangeMapping range = new() {
OriginStart = seed,
DestinationStart = seed,
Length = seedLen,
};
ranges.Add(range);
i += 2;
}
List<AlmanacRangeMapping> mappedRanges = almanac?.ApplyMapping(ranges) ?? ranges;
long minLocation = mappedRanges.Select(range => range.DestinationStart).Min();
return minLocation.ToString();
}
@@ -176,15 +179,119 @@ public class Day05 : IDay
{
public long DestinationStart { get; init; }
public long OriginStart { get; init; }
public long Lenght { get; init; }
public long Length { get; init; }
public long? Apply(long value)
{
if (value < OriginStart) { return null; }
long diff = value - OriginStart;
if (diff >= Lenght) { return null; }
if (diff >= Length) { return null; }
return DestinationStart + diff;
}
public class ClipResult
{
public AlmanacRangeMapping? Clipped { get; init; }
public AlmanacRangeMapping? PreClip { get; init; }
public AlmanacRangeMapping? PostClip { get; init; }
}
public ClipResult Clip(AlmanacRangeMapping range)
{
long rangeOriginEnd = range.OriginStart + range.Length;
if (rangeOriginEnd < OriginStart)
{
return new ClipResult { PreClip = range, };
}
long originEnd = OriginStart + Length;
if (originEnd < range.OriginStart)
{
return new ClipResult { PostClip = range, };
}
if (OriginStart <= range.OriginStart)
{
if (range.OriginStart == originEnd)
{
return new ClipResult() {
PostClip = range,
};
}
if (rangeOriginEnd <= originEnd)
{
long lenInside = range.OriginStart - OriginStart;
return new ClipResult() {
Clipped = range with {
DestinationStart = DestinationStart + lenInside,
},
};
}
if (rangeOriginEnd >= originEnd)
{
long lenInside = range.OriginStart - OriginStart;
long lenOverlap = originEnd - range.OriginStart;
return new ClipResult() {
Clipped = range with {
DestinationStart = DestinationStart + lenInside,
Length = Length - lenInside,
},
PostClip = new AlmanacRangeMapping {
OriginStart = range.OriginStart + lenOverlap,
DestinationStart = range.DestinationStart + lenOverlap,
Length = range.Length - lenOverlap,
},
};
}
}
if (range.OriginStart < OriginStart)
{
if (rangeOriginEnd <= originEnd)
{
long lenClipped = (rangeOriginEnd) - OriginStart;
long lenPre = range.Length - lenClipped;
return new ClipResult() {
PreClip = range with {
Length = lenPre,
},
Clipped = lenClipped > 0
? this with {
Length = lenClipped,
}
: null,
};
}
if (rangeOriginEnd > originEnd)
{
long lenClipped = Length;
long lenPre = OriginStart - range.OriginStart;
long lenToPost = originEnd - range.OriginStart;
long lenPost = rangeOriginEnd - originEnd;
return new ClipResult() {
PreClip = range with {
Length = lenPre,
},
Clipped = this with {
Length = lenClipped,
},
PostClip = new AlmanacRangeMapping {
OriginStart = range.OriginStart + lenToPost,
DestinationStart = range.DestinationStart + lenToPost,
Length = lenPost,
},
};
}
}
return new ClipResult();
}
}
public class AlmanacMapping
@@ -217,7 +324,7 @@ public class Day05 : IDay
AlmanacRangeMapping rangeMapping = new() {
DestinationStart = Convert.ToInt64(mappingParts[0]),
OriginStart = Convert.ToInt64(mappingParts[1]),
Lenght = Convert.ToInt64(mappingParts[2]),
Length = Convert.ToInt64(mappingParts[2]),
};
mapping.RangeMappings.Add(rangeMapping);
} while (true);
@@ -236,6 +343,33 @@ public class Day05 : IDay
}
return value;
}
public List<AlmanacRangeMapping> Apply(AlmanacRangeMapping range)
{
List<AlmanacRangeMapping> unMappedRanges = new() {
range,
};
List<AlmanacRangeMapping> newUnMappedRanges = new();
List<AlmanacRangeMapping> mappedRanges = new();
int i = 0;
while (RangeMappings.Count > i)
{
AlmanacRangeMapping rangeMapping = RangeMappings[i];
for (int j = 0; j < unMappedRanges.Count; j++)
{
AlmanacRangeMapping.ClipResult result = rangeMapping.Clip(unMappedRanges[j]);
if (result.Clipped != null) { mappedRanges.Add(result.Clipped.Value); }
if (result.PreClip != null) { newUnMappedRanges.Add(result.PreClip.Value); }
if (result.PostClip != null) { newUnMappedRanges.Add(result.PostClip.Value); }
}
unMappedRanges = newUnMappedRanges;
newUnMappedRanges = new List<AlmanacRangeMapping>();
i++;
}
return mappedRanges.Union(unMappedRanges).ToList();
}
}
public class Almanac
@@ -277,5 +411,23 @@ public class Day05 : IDay
}
return value;
}
public List<AlmanacRangeMapping> ApplyMapping(List<AlmanacRangeMapping> ranges)
{
List<AlmanacRangeMapping> currentRanges = ranges;
int i = 0;
while (i < Mappings.Count)
{
List<AlmanacRangeMapping> mappedRanges = currentRanges
.Select(range => Mappings[i].Apply(range))
.SelectMany(x => x)
.ToList();
currentRanges = mappedRanges
.Select(x => x with { OriginStart = x.DestinationStart, })
.ToList();
i++;
}
return currentRanges;
}
}
}