Solve 2021 day 13

2021/13_fold.py

@@ -0,0 +1,37 @@
+#!/usr/bin/env python3
+import sys
+
+def read_dots(f):
+    for line in f:
+        if line == '\n':
+            break
+        x, y = line.split(',')
+        yield int(x), int(y)
+
+def read_folds(f):
+    for line in f:
+        axis, at = line.split()[-1].split('=')
+        yield axis == 'y', int(at)
+
+def flip(i, at):
+    return i if i < at else i - 2 * (i - at)
+
+def fold(dots, up, at):
+    return {(x, flip(y, at)) if up else (flip(x, at), y) for x, y in dots}
+
+def plot(dots):
+    xmin = min(x for x, y in dots)
+    xmax = max(x for x, y in dots)
+    ymin = min(y for x, y in dots)
+    ymax = max(y for x, y in dots)
+    for y in range(ymin, ymax + 1):
+        print(''.join(' #'[(x, y) in dots] for x in range(xmin, xmax + 1)))
+
+dots = list(read_dots(sys.stdin))
+first_fold, *other_folds = read_folds(sys.stdin)
+dots = fold(dots, *first_fold)
+print(len(dots))
+
+for up, at in other_folds:
+    dots = fold(dots, up, at)
+plot(dots)

2021/input/13

@@ -0,0 +1,879 @@
+77,882
+656,319
+787,478
+0,487
+1158,150
+462,543
+1073,509
+989,886
+1014,225
+38,105
+865,52
+510,395
+979,602
+959,554
+72,29
+10,493
+318,722
+637,189
+1231,406
+152,821
+1124,728
+820,207
+328,323
+430,381
+668,21
+618,884
+691,879
+345,427
+162,687
+739,394
+577,847
+965,427
+495,245
+52,352
+366,260
+35,849
+1285,89
+402,677
+254,141
+987,327
+808,270
+619,401
+1203,233
+1096,198
+1086,466
+452,283
+243,122
+1051,299
+692,458
+102,285
+815,649
+930,660
+319,777
+472,506
+291,431
+656,166
+527,316
+1145,138
+164,655
+646,473
+1293,203
+142,21
+1208,18
+1039,885
+502,753
+694,109
+776,262
+132,88
+1283,638
+1014,669
+912,403
+1145,756
+1069,672
+421,243
+1227,430
+855,92
+870,198
+7,726
+1017,14
+738,459
+979,327
+1118,239
+562,865
+137,730
+83,430
+743,331
+636,448
+1148,547
+254,753
+960,462
+102,130
+1029,549
+73,58
+821,756
+1288,812
+199,828
+413,40
+82,435
+308,395
+107,233
+440,368
+569,670
+1109,206
+719,875
+494,54
+333,8
+1004,348
+800,164
+411,724
+77,210
+900,165
+80,340
+649,522
+85,33
+1058,677
+291,543
+594,18
+758,738
+512,546
+1279,854
+124,312
+619,15
+247,138
+624,465
+1102,156
+165,138
+42,694
+470,39
+984,123
+1153,43
+132,478
+961,5
+932,264
+850,358
+763,698
+490,655
+191,414
+959,106
+336,647
+656,347
+1104,441
+1067,859
+36,436
+733,847
+370,428
+97,712
+584,276
+252,441
+411,170
+131,430
+1076,494
+271,9
+201,206
+1178,478
+572,459
+3,567
+803,694
+1186,507
+442,84
+571,532
+1069,525
+194,806
+818,871
+1230,340
+770,534
+304,840
+381,219
+1171,513
+338,361
+351,340
+336,23
+1039,512
+975,616
+272,782
+796,716
+160,287
+1223,10
+201,458
+815,245
+678,432
+825,3
+420,597
+773,400
+572,817
+1231,210
+624,88
+940,68
+1208,609
+855,316
+840,605
+1308,70
+738,817
+1158,821
+577,460
+497,182
+629,421
+333,522
+131,464
+1178,806
+325,500
+677,329
+666,52
+1218,400
+678,502
+1283,190
+1014,241
+1173,476
+741,236
+512,796
+1272,120
+1064,788
+433,480
+865,730
+187,177
+185,378
+30,88
+7,441
+743,322
+303,289
+959,65
+162,347
+577,47
+1131,822
+1069,623
+22,604
+1111,380
+370,792
+636,619
+1081,848
+644,52
+373,702
+994,361
+992,396
+1265,736
+897,301
+929,675
+383,830
+234,404
+35,718
+349,889
+291,463
+1293,189
+1047,413
+35,243
+358,673
+1178,416
+185,516
+562,404
+77,854
+513,826
+1300,493
+616,102
+351,554
+494,392
+698,68
+1280,241
+858,312
+537,400
+1223,93
+748,628
+940,826
+77,434
+489,618
+546,560
+497,712
+176,145
+239,577
+927,134
+798,796
+127,474
+430,605
+23,849
+813,712
+960,716
+753,253
+1218,381
+161,84
+800,282
+452,312
+562,490
+70,276
+1289,329
+673,33
+1268,550
+1280,528
+184,21
+480,567
+167,873
+488,432
+137,612
+637,637
+358,653
+961,602
+848,705
+154,386
+718,725
+1108,333
+1064,211
+880,381
+741,670
+291,203
+416,880
+45,736
+1109,688
+229,29
+986,166
+160,840
+246,106
+713,190
+651,516
+1131,520
+348,404
+825,739
+1205,737
+397,19
+1223,796
+510,613
+1292,843
+811,616
+326,508
+398,715
+731,801
+97,46
+334,236
+199,66
+114,810
+1226,492
+1115,520
+12,873
+1111,540
+683,704
+549,737
+1170,390
+959,452
+899,724
+986,280
+686,241
+406,450
+499,54
+1253,190
+818,23
+470,289
+1016,870
+597,190
+1186,835
+160,502
+1275,849
+959,177
+1061,637
+895,658
+348,490
+780,731
+139,605
+1260,1
+679,106
+1058,350
+902,211
+1289,565
+579,93
+296,806
+514,147
+266,290
+256,381
+1170,626
+841,528
+184,263
+947,203
+562,46
+632,290
+736,106
+184,873
+813,3
+288,430
+224,802
+1076,490
+1150,502
+800,612
+219,213
+252,350
+185,304
+448,632
+708,352
+880,130
+868,810
+239,317
+1228,613
+562,513
+713,638
+550,700
+976,658
+346,171
+420,774
+647,117
+523,128
+53,784
+678,530
+534,120
+378,159
+1193,58
+577,40
+664,473
+530,835
+562,494
+656,534
+1203,661
+25,25
+281,549
+291,691
+1158,243
+1056,141
+830,701
+823,469
+713,704
+910,801
+157,851
+631,676
+1173,85
+472,730
+1014,806
+502,598
+296,877
+754,63
+291,351
+1091,233
+977,451
+383,642
+1071,236
+818,471
+862,693
+1186,59
+1274,436
+940,428
+1307,775
+862,632
+604,750
+139,513
+1307,516
+1059,353
+1203,698
+276,264
+517,866
+821,187
+166,290
+523,794
+1256,110
+587,747
+739,464
+182,501
+562,266
+840,42
+1275,243
+604,1
+816,287
+713,256
+932,630
+1002,395
+567,331
+239,236
+989,74
+1233,460
+55,64
+664,535
+1086,381
+331,602
+273,110
+899,170
+686,689
+1305,451
+1086,285
+932,735
+114,362
+698,694
+1158,40
+1218,439
+331,327
+698,200
+1215,859
+739,532
+654,534
+1158,624
+1196,810
+1200,128
+808,73
+513,131
+241,525
+408,659
+162,547
+92,886
+556,63
+259,299
+666,742
+592,169
+7,117
+440,78
+137,282
+616,785
+109,219
+70,403
+320,236
+412,103
+830,822
+899,618
+30,653
+1280,770
+1144,40
+1310,280
+1041,862
+947,15
+989,8
+1091,213
+349,292
+1086,428
+862,245
+154,508
+346,723
+234,754
+413,271
+462,207
+328,386
+681,869
+186,280
+753,176
+731,93
+808,262
+445,556
+494,840
+557,718
+1198,78
+80,820
+140,147
+415,658
+1171,269
+1076,588
+105,737
+616,445
+855,578
+1005,154
+542,646
+1128,393
+517,164
+912,491
+1067,35
+242,791
+209,756
+947,463
+547,698
+411,324
+644,376
+912,715
+810,60
+880,428
+956,493
+112,78
+947,400
+398,65
+1115,254
+523,640
+567,563
+1255,830
+1170,147
+1288,432
+851,702
+925,414
+160,54
+547,661
+1109,212
+335,616
+488,40
+793,364
+580,124
+189,84
+1058,322
+716,18
+80,422
+102,156
+107,698
+1108,878
+433,605
+164,239
+890,120
+398,403
+664,807
+546,782
+748,266
+485,331
+415,236
+653,730
+1124,280
+0,575
+1121,362
+124,59
+545,667
+674,448
+1141,155
+899,84
+331,154
+515,513
+1071,577
+82,116
+1101,108
+1225,861
+813,451
+637,33
+1125,378
+1166,169
+1038,782
+97,624
+249,189
+1250,18
+1223,523
+499,278
+1272,445
+31,854
+787,416
+897,593
+97,396
+487,425
+691,849
+858,449
+430,285
+1101,351
+189,28
+1285,25
+981,75
+855,802
+321,8
+574,340
+947,431
+753,718
+411,618
+224,285
+334,658
+331,740
+35,270
+929,558
+497,184
+159,103
+249,12
+497,891
+108,334
+378,264
+880,876
+296,669
+1304,236
+830,72
+31,488
+167,425
+75,801
+1258,352
+3,775
+912,65
+363,543
+44,828
+1007,666
+1091,661
+84,402
+855,540
+1305,73
+743,563
+179,520
+1073,833
+1026,792
+85,147
+656,280
+271,512
+889,243
+358,241
+632,392
+1275,270
+1063,138
+87,371
+880,285
+880,289
+1111,578
+1125,516
+1037,219
+445,52
+1168,873
+462,705
+1223,563
+195,254
+169,155
+117,58
+53,558
+54,560
+982,508
+967,541
+1205,157
+858,344
+619,879
+848,257
+514,716
+1047,481
+1014,877
+114,84
+157,43
+1059,801
+899,324
+686,1
+445,584
+25,537
+904,2
+649,373
+284,792
+452,102
+1250,466
+388,92
+1233,210
+1001,427
+28,413
+201,240
+385,414
+803,200
+571,500
+517,197
+378,735
+370,68
+733,47
+646,535
+60,466
+1288,604
+8,535
+38,102
+1148,743
+306,289
+1136,712
+822,432
+679,788
+748,513
+764,560
+1230,442
+85,658
+1058,453
+27,638
+698,708
+485,3
+1019,351
+899,810
+681,421
+1213,396
+813,67
+624,429
+950,362
+991,777
+1064,198
+363,203
+366,109
+1044,738
+80,452
+328,235
+686,429
+647,168
+842,840
+405,294
+1136,633
+1126,21
+656,278
+624,893
+691,401
+350,462
+345,705
+480,822
+408,235
+1068,791
+1143,425
+114,756
+1193,584
+134,593
+709,784
+686,256
+348,714
+273,675
+1,164
+600,782
+1213,46
+350,716
+1196,756
+1183,474
+1069,719
+1002,638
+571,394
+349,602
+736,459
+494,432
+497,3
+1293,33
+269,862
+202,16
+694,449
+294,810
+764,112
+493,707
+199,540
+619,45
+1186,312
+1126,605
+678,604
+1193,836
+241,672
+1019,203
+28,481
+597,638
+1067,122
+612,344
+201,212
+400,801
+237,833
+306,348
+425,865
+152,632
+381,675
+239,3
+574,659
+870,368
+20,457
+1067,618
+552,156
+686,893
+890,196
+502,29
+787,794
+82,281
+599,700
+1041,249
+351,177
+303,228
+1225,672
+502,821
+391,481
+400,93
+430,18
+448,262
+1019,463
+780,59
+644,742
+793,164
+492,471
+87,115
+547,644
+574,554
+694,893
+25,89
+1121,866
+490,239
+1256,560
+739,362
+405,257
+430,876
+730,124
+370,102
+366,634
+95,411
+523,766
+452,113
+1236,772
+544,10
+162,151
+489,187
+663,329
+763,196
+195,702
+527,578
+766,10
+979,119
+930,234
+780,582
+
+fold along x=655
+fold along y=447
+fold along x=327
+fold along y=223
+fold along x=163
+fold along y=111
+fold along x=81
+fold along y=55
+fold along x=40
+fold along y=27
+fold along y=13
+fold along y=6