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Day 5 solution

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There is a lot to be disliked here, starting with the Line Length calculation, which I'm sure I'm just totally overthinking or otherwise being dumb about, to the way I'm picking the next point while moving along the line.

Also, TIL how much of a difference a good GetHashCode() override can make when comparing/equating custom struct instances. Not implementing GetHashCode() on this solution resulted in ~250ms runtime on my PC. Implementing a "bad" GetHashCode() (which was `return x.GetHashCode() | y.GetHashCode();` which seemed fine to me ¯\_(ツ)_/¯) resulted in >1s runtime on my PC. Using this implementation (HashCode.Combine()) results in ~25ms runtime on my PC. Those numbers are with nothing changing other than the implementation of GetHashCode() on struct Point.

I also disabled nullability in my quest to improve performance here. The compiler was complaining that my Equals() override wasn't equivalent because of nullability, so it had to be `object? obj` which I didn't care for since this was a value type and not a reference type.
This commit is contained in:
Chris Pickett
2021-12-05 11:18:19 -06:00
parent 3dc7e1ccde
commit 7d93691276
4 changed files with 635 additions and 1 deletions
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5
advent-of-code-2021.csproj
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@ -5,7 +5,7 @@
<TargetFramework>net6.0</TargetFramework> <TargetFramework>net6.0</TargetFramework>
<RootNamespace>aoc2021</RootNamespace> <RootNamespace>aoc2021</RootNamespace>
<ImplicitUsings>enable</ImplicitUsings> <ImplicitUsings>enable</ImplicitUsings>
<Nullable>enable</Nullable> <Nullable>disable</Nullable>
<ProduceReferenceAssembly>False</ProduceReferenceAssembly> <ProduceReferenceAssembly>False</ProduceReferenceAssembly>
<EnforceCodeStyleInBuild>True</EnforceCodeStyleInBuild> <EnforceCodeStyleInBuild>True</EnforceCodeStyleInBuild>
</PropertyGroup> </PropertyGroup>
@ -27,6 +27,9 @@
<None Update="inputs\03.txt"> <None Update="inputs\03.txt">
<CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory> <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
</None> </None>
<None Update="inputs\05.txt">
<CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
</None>
</ItemGroup> </ItemGroup>
</Project> </Project>

500
inputs/05.txt Normal file
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@ -0,0 +1,500 @@
822,976 -> 822,117
387,419 -> 387,468
659,275 -> 318,616
535,940 -> 684,940
294,427 -> 294,88
568,922 -> 425,779
99,265 -> 97,267
534,387 -> 402,387
958,268 -> 958,315
234,714 -> 234,305
507,257 -> 507,328
455,384 -> 455,645
483,641 -> 483,138
410,249 -> 825,249
609,836 -> 528,836
77,913 -> 77,780
478,93 -> 478,123
391,695 -> 715,695
972,586 -> 649,586
936,955 -> 39,58
168,791 -> 944,15
934,222 -> 811,222
372,683 -> 372,93
911,676 -> 771,816
147,34 -> 147,97
524,498 -> 986,960
791,924 -> 239,372
293,145 -> 776,628
195,472 -> 195,31
884,649 -> 215,649
95,53 -> 95,966
484,111 -> 866,493
564,913 -> 681,913
36,362 -> 486,362
762,146 -> 762,323
330,334 -> 937,334
704,714 -> 744,714
56,12 -> 958,914
855,784 -> 855,629
206,665 -> 206,681
436,629 -> 117,948
414,685 -> 414,54
788,401 -> 788,842
442,270 -> 309,270
606,711 -> 416,521
45,630 -> 45,543
221,192 -> 221,537
629,544 -> 417,544
362,605 -> 885,605
988,928 -> 738,678
460,758 -> 981,237
561,26 -> 561,409
543,186 -> 833,186
963,409 -> 910,462
55,129 -> 742,816
245,27 -> 806,27
318,137 -> 318,592
762,700 -> 762,483
436,341 -> 436,654
641,725 -> 641,227
486,446 -> 56,16
113,821 -> 113,196
740,534 -> 821,534
606,765 -> 125,284
614,786 -> 371,786
215,519 -> 215,814
274,496 -> 482,496
131,210 -> 473,552
701,68 -> 701,395
81,713 -> 81,104
458,677 -> 622,677
237,225 -> 237,810
384,246 -> 384,644
411,876 -> 445,910
182,814 -> 182,184
643,858 -> 407,858
698,621 -> 971,348
309,253 -> 511,51
990,368 -> 671,368
129,619 -> 750,619
382,803 -> 382,635
629,270 -> 415,484
550,101 -> 56,595
971,745 -> 971,589
353,947 -> 786,514
71,931 -> 974,28
915,621 -> 363,69
650,547 -> 650,596
884,228 -> 574,228
833,476 -> 833,824
24,722 -> 24,885
401,508 -> 401,553
452,106 -> 740,106
255,840 -> 60,840
551,609 -> 551,767
799,572 -> 356,129
343,138 -> 945,740
77,766 -> 77,72
190,760 -> 190,341
978,583 -> 911,583
557,18 -> 557,640
673,276 -> 882,276
143,348 -> 775,980
776,803 -> 776,812
38,348 -> 38,463
648,567 -> 210,567
468,934 -> 534,868
966,987 -> 26,47
471,465 -> 126,465
26,29 -> 940,943
416,340 -> 361,285
702,66 -> 702,673
34,964 -> 951,47
156,791 -> 65,791
635,678 -> 355,678
898,13 -> 898,909
644,334 -> 644,155
304,93 -> 445,93
946,934 -> 930,918
376,289 -> 317,348
460,491 -> 500,491
761,605 -> 866,710
252,534 -> 413,534
178,23 -> 895,740
677,90 -> 677,592
905,985 -> 211,291
963,65 -> 963,214
853,617 -> 815,617
576,532 -> 319,275
134,59 -> 829,754
926,948 -> 11,33
46,279 -> 760,279
60,389 -> 60,340
49,264 -> 561,776
912,322 -> 790,322
825,205 -> 825,433
637,693 -> 780,693
891,196 -> 200,196
537,604 -> 604,604
870,75 -> 870,342
518,173 -> 455,110
666,67 -> 919,67
536,128 -> 137,527
698,41 -> 44,41
936,982 -> 106,152
780,488 -> 780,918
968,313 -> 56,313
759,36 -> 140,36
111,605 -> 111,430
609,165 -> 54,720
388,452 -> 745,809
986,12 -> 11,987
193,614 -> 335,756
113,239 -> 38,164
715,145 -> 305,555
632,13 -> 508,137
698,673 -> 698,101
954,225 -> 720,225
626,688 -> 626,476
636,697 -> 91,152
228,210 -> 621,210
83,325 -> 989,325
644,358 -> 644,648
481,183 -> 481,901
803,160 -> 250,713
648,96 -> 913,96
921,17 -> 26,912
844,256 -> 844,485
190,138 -> 578,526
383,527 -> 357,501
529,212 -> 757,440
646,399 -> 944,399
961,681 -> 961,178
40,236 -> 484,680
432,465 -> 832,465
988,989 -> 10,11
850,800 -> 850,292
25,97 -> 372,97
383,248 -> 383,125
577,488 -> 852,763
607,322 -> 432,147
611,637 -> 614,637
853,677 -> 755,677
953,225 -> 953,333
984,978 -> 45,39
95,981 -> 314,981
550,400 -> 327,177
929,893 -> 99,63
958,293 -> 152,293
68,656 -> 563,161
45,506 -> 45,925
271,566 -> 289,566
460,440 -> 920,900
392,788 -> 392,263
946,335 -> 946,171
833,405 -> 876,448
268,188 -> 268,678
881,40 -> 30,40
317,84 -> 277,84
415,917 -> 415,358
28,654 -> 28,646
346,461 -> 346,724
935,954 -> 935,362
121,840 -> 121,38
29,55 -> 344,370
774,649 -> 621,649
31,985 -> 396,620
85,579 -> 85,131
181,886 -> 978,89
284,969 -> 284,95
669,943 -> 54,328
72,509 -> 72,857
460,557 -> 986,31
555,460 -> 555,928
921,961 -> 666,706
11,13 -> 951,953
173,948 -> 173,982
680,422 -> 503,245
443,232 -> 443,630
829,487 -> 773,487
176,631 -> 631,176
860,866 -> 559,866
317,537 -> 624,537
937,199 -> 753,199
484,545 -> 293,736
84,616 -> 489,211
340,166 -> 340,876
47,210 -> 47,961
852,404 -> 852,804
831,565 -> 454,188
236,621 -> 556,941
734,640 -> 734,728
756,357 -> 756,433
102,220 -> 157,220
153,800 -> 104,849
710,585 -> 710,666
724,298 -> 724,698
762,257 -> 123,896
402,642 -> 402,964
549,108 -> 945,108
301,966 -> 851,966
399,903 -> 101,605
194,857 -> 605,857
291,373 -> 85,373
601,597 -> 844,597
362,335 -> 362,107
769,66 -> 107,66
49,373 -> 49,143
96,800 -> 894,800
468,116 -> 557,116
549,206 -> 956,206
918,972 -> 35,89
688,632 -> 106,632
267,338 -> 414,485
258,392 -> 258,107
604,964 -> 139,499
975,191 -> 977,191
861,960 -> 93,192
979,570 -> 439,570
961,21 -> 63,919
312,419 -> 881,419
507,779 -> 507,79
775,447 -> 645,447
34,928 -> 626,928
786,515 -> 786,34
81,269 -> 734,922
938,264 -> 266,264
799,271 -> 799,713
765,860 -> 765,43
967,869 -> 135,37
920,757 -> 602,439
419,814 -> 655,814
22,40 -> 472,490
136,672 -> 770,672
667,860 -> 288,481
311,305 -> 311,674
163,569 -> 163,120
801,885 -> 139,223
551,214 -> 551,207
594,979 -> 942,631
347,286 -> 448,185
161,134 -> 855,828
861,864 -> 20,23
309,388 -> 309,676
582,383 -> 86,879
930,58 -> 206,782
538,925 -> 242,925
379,890 -> 704,565
338,350 -> 338,419
916,870 -> 916,283
101,928 -> 402,627
899,696 -> 899,179
96,62 -> 658,624
950,46 -> 11,985
914,510 -> 910,510
98,116 -> 556,116
165,151 -> 913,899
822,76 -> 41,76
878,97 -> 75,900
476,623 -> 873,623
257,494 -> 746,983
638,23 -> 638,778
969,212 -> 259,212
186,146 -> 923,883
799,822 -> 736,822
628,876 -> 532,780
388,604 -> 388,617
591,949 -> 868,949
92,372 -> 107,357
274,691 -> 254,671
169,917 -> 169,317
792,27 -> 710,27
215,645 -> 713,147
886,498 -> 689,498
955,129 -> 214,870
561,380 -> 375,380
391,849 -> 391,75
181,677 -> 759,677
347,394 -> 347,969
52,383 -> 875,383
498,827 -> 729,596
125,832 -> 125,18
799,711 -> 105,711
952,884 -> 129,61
123,269 -> 123,906
792,934 -> 12,154
955,253 -> 753,253
676,957 -> 676,264
437,35 -> 40,35
661,166 -> 509,14
72,978 -> 270,978
554,472 -> 554,627
914,291 -> 464,741
450,841 -> 827,841
846,694 -> 846,281
391,97 -> 890,596
859,512 -> 685,338
349,564 -> 349,187
473,442 -> 896,19
383,949 -> 383,276
568,596 -> 875,596
298,43 -> 298,504
482,632 -> 12,632
44,441 -> 44,978
210,502 -> 210,712
191,391 -> 191,196
27,683 -> 27,840
47,13 -> 960,926
81,779 -> 81,952
914,96 -> 145,96
444,175 -> 151,175
293,934 -> 293,488
106,867 -> 221,982
669,576 -> 858,576
713,142 -> 84,771
60,923 -> 299,923
376,307 -> 281,307
904,53 -> 41,916
763,495 -> 588,495
62,899 -> 843,899
63,939 -> 592,410
294,588 -> 294,437
920,101 -> 879,142
688,527 -> 688,357
679,854 -> 950,854
636,765 -> 329,765
939,87 -> 62,87
952,560 -> 952,193
466,761 -> 32,327
189,245 -> 876,932
42,675 -> 42,311
787,257 -> 62,982
934,983 -> 64,113
548,522 -> 626,522
942,322 -> 942,276
267,298 -> 267,385
632,241 -> 632,117
192,644 -> 192,507
627,33 -> 627,175
350,650 -> 350,157
807,239 -> 113,933
294,713 -> 87,713
81,530 -> 453,530
539,61 -> 240,61
893,76 -> 893,776
39,49 -> 978,988
733,17 -> 606,144
19,408 -> 493,408
364,639 -> 43,639
873,946 -> 69,142
825,875 -> 233,875
708,408 -> 197,919
990,202 -> 990,32
370,393 -> 664,393
764,472 -> 284,472
308,685 -> 308,541
917,68 -> 45,940
397,794 -> 524,667
525,674 -> 313,462
475,981 -> 297,981
728,152 -> 40,840
265,257 -> 162,257
621,847 -> 828,640
547,927 -> 21,401
351,676 -> 357,676
668,640 -> 668,228
138,736 -> 446,736
912,687 -> 912,817
718,278 -> 718,779
674,786 -> 986,474
812,273 -> 891,273
46,341 -> 46,831
404,464 -> 118,464
277,926 -> 114,763
231,786 -> 106,786
266,721 -> 446,541
42,80 -> 675,713
422,116 -> 422,344
922,543 -> 922,511
525,150 -> 525,599
862,288 -> 498,288
961,432 -> 961,693
895,876 -> 895,837
619,361 -> 174,361
275,673 -> 275,415
950,179 -> 405,179
460,460 -> 460,405
222,872 -> 222,959
451,403 -> 21,833
570,367 -> 570,147
260,792 -> 82,970
586,159 -> 108,159
956,25 -> 55,926
71,645 -> 988,645
540,438 -> 44,934
230,160 -> 395,160
811,106 -> 811,598
819,741 -> 596,741
347,731 -> 347,198
503,580 -> 495,580
30,706 -> 603,133
257,498 -> 619,498
232,784 -> 359,784
826,708 -> 396,708
14,977 -> 895,96
964,192 -> 279,192
611,282 -> 611,460
207,903 -> 207,882
969,10 -> 22,957
403,599 -> 970,32
712,671 -> 712,733
795,422 -> 235,422
47,965 -> 939,73
925,839 -> 275,189
102,593 -> 973,593
389,768 -> 389,493
234,365 -> 624,365
50,901 -> 50,702
345,573 -> 638,866
798,280 -> 111,967
258,556 -> 258,978
966,57 -> 88,935
171,279 -> 171,130
238,727 -> 947,727
683,777 -> 290,777
552,308 -> 552,150
81,91 -> 911,921
845,698 -> 845,735
712,241 -> 26,927
120,813 -> 716,217
947,10 -> 25,932
395,381 -> 338,324
408,989 -> 408,529
600,574 -> 600,557
46,567 -> 46,980
983,14 -> 10,987
984,568 -> 642,568
543,250 -> 543,80
765,534 -> 108,534
89,213 -> 120,213
893,813 -> 271,191
133,178 -> 133,654
468,689 -> 468,677
970,203 -> 970,952
892,322 -> 892,417
593,735 -> 152,294
839,75 -> 839,964
746,413 -> 89,413
535,595 -> 535,633
771,646 -> 614,489
572,852 -> 572,718
125,35 -> 838,748
122,812 -> 179,812
467,243 -> 188,243
713,850 -> 51,188
633,279 -> 932,578
428,230 -> 216,18
94,921 -> 973,42
513,609 -> 513,507
826,358 -> 330,854

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src/05.cs Normal file
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@ -0,0 +1,130 @@
using System.Diagnostics;
using System.Text.RegularExpressions;
namespace aoc2021
{
internal class Day05
{
private static readonly Regex lineRegex = new(@"(?<x1>\d+),(?<y1>\d+) -> (?<x2>\d+),(?<y2>\d+)", RegexOptions.Compiled);
[DebuggerDisplay("{x},{y}")]
struct Point : IEquatable<Point>
{
public int X { get; init; }
public int Y { get; init; }
public bool Equals(Point other) => X == other.X && Y == other.Y;
public override bool Equals(object obj) => obj is Point point && Equals(point);
public override int GetHashCode() => HashCode.Combine(X, Y);
}
[DebuggerDisplay("{start} -> {end}")]
struct Line
{
public Point Start { get; init; }
public Point End { get; init; }
public int Length
{
get
{
// this is bad and i feel bad
if (Start.X == End.X || Start.Y == End.Y)
{
return Math.Abs((End.X - Start.X) + (End.Y - Start.Y));
}
return Math.Abs(Start.X - End.X);
}
}
}
internal static void Go()
{
Logger.Log("Day 5");
Logger.Log("-----");
var lines = File.ReadAllLines("inputs/05.txt");
List<Line> segments = new();
foreach (var line in lines)
{
var match = lineRegex.Match(line);
Line segment = new()
{
Start = new Point()
{
X = Convert.ToInt32(match.Groups["x1"].Value),
Y = Convert.ToInt32(match.Groups["y1"].Value),
},
End = new Point()
{
X = Convert.ToInt32(match.Groups["x2"].Value),
Y = Convert.ToInt32(match.Groups["y2"].Value)
},
};
segments.Add(segment);
}
Part1(segments);
Part2(segments);
Logger.Log("");
}
private static void Part1(IEnumerable<Line> lines)
{
using var t = new Timer();
int numPointsGreater = Solve(lines, (line) => !(line.Start.X == line.End.X || line.Start.Y == line.End.Y));
Logger.Log($"part1: {numPointsGreater}");
}
private static void Part2(IEnumerable<Line> lines)
{
using var t = new Timer();
int numPointsGreater = Solve(lines, (line) => false);
Logger.Log($"part2: {numPointsGreater}");
}
private static int Solve(IEnumerable<Line> lines, Func<Line, bool> filter)
{
Dictionary<Point, int> coveredPoints = new();
int numPointsGreater = 0;
foreach (var line in lines)
{
if (filter(line))
{
continue;
}
for (int i = 0; i <= line.Length; i++)
{
int x = line.Start.X;
int y = line.Start.Y;
if (line.Start.X != line.End.X)
{
x += (line.Start.X > line.End.X ? -1 : 1) * i;
}
if (line.Start.Y != line.End.Y)
{
y += (line.Start.Y > line.End.Y ? -1 : 1) * i;
}
Point point = new() { X = x, Y = y };
if (!coveredPoints.TryGetValue(point, out int curr))
{
coveredPoints.Add(point, curr);
}
if (curr == 1)
{
numPointsGreater++;
}
coveredPoints[point] = curr + 1;
}
}
return numPointsGreater;
}
}
}

1
src/main.cs
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@ -1,2 +1,3 @@
aoc2021.Day02.Go(); aoc2021.Day02.Go();
aoc2021.Day03.Go(); aoc2021.Day03.Go();
aoc2021.Day05.Go();