From: Brett Parker <iDunno@sommitrealweird.co.uk>
Date: Tue, 14 Dec 2021 03:19:06 +0000 (+0000)
Subject: Day 13 (start)
X-Git-Url: https://git.sommitrealweird.co.uk/advent-of-code-2021.git/commitdiff_plain/16c6bf02b28e2d22ce893acdd4de2e4094316e8d?ds=inline

Day 13 (start)
---

diff --git a/day13/example.txt b/day13/example.txt
new file mode 100644
index 0000000..282114c
--- /dev/null
+++ b/day13/example.txt
@@ -0,0 +1,21 @@
+6,10
+0,14
+9,10
+0,3
+10,4
+4,11
+6,0
+6,12
+4,1
+0,13
+10,12
+3,4
+3,0
+8,4
+1,10
+2,14
+8,10
+9,0
+
+fold along y=7
+fold along x=5
diff --git a/day13/fold.sh b/day13/fold.sh
new file mode 100755
index 0000000..83e1585
--- /dev/null
+++ b/day13/fold.sh
@@ -0,0 +1,157 @@
+#!/bin/bash
+
+set -u
+
+declare -a points=()
+declare -a folds=()
+
+filename="${1:-example.txt}"
+exec 3<"$filename"
+
+max_x=0
+max_y=0
+
+while read -u 3 line; do
+    if [ "$line" == "" ]; then
+        break
+    fi
+    x=${line%,*}
+    y=${line#*,}
+    if [ $x -gt $max_x ]; then
+        max_x=$x
+    fi
+    if [ $y -gt $max_y ]; then
+        max_y=$y
+    fi
+    points+=($line)
+done
+
+((max_x+=1))
+((max_y+=1))
+
+while read -u 3 line; do
+    folds+=(${line#fold along })
+done
+
+display_map() {
+    for (( y=0; y<$max_y; y++ )); do
+        for (( x=0; x<$max_x; x++ )); do
+            offset=$(((y*$max_x) + $x))
+            case "${map[$offset]}" in
+                0)
+                    echo -n "."
+                    ;;
+                1)
+                    echo -n "#"
+                    ;;
+            esac
+        done
+        echo
+    done
+}
+
+declare -a map
+
+# now build a map
+for (( a=0; a<$(($max_x * $max_y)); a++ )); do
+    map[$a]=0
+done
+
+for point in "${points[@]}"; do
+    x=${point%,*}
+    y=${point#*,}
+    offset=$((($y*$max_x)+$x))
+    map[$offset]=1
+done
+
+fold() {
+    local line="$1"
+    local axis=${line%=*}
+    local point=${line#*=}
+    local dot="."
+
+    declare -a new_map=()
+
+    case $axis in
+        x)
+            local new_max_x=$(($max_x - $point - 1))
+            if [ $point -gt $new_max_x ]; then
+                new_max_x=$point
+            fi
+            local adj=$((max_x % 2))
+            for (( y=0; y<$max_y; y++ )); do
+                for (( x=0; x<$new_max_x; x++ )); do
+                    x_1=$(($point - $new_max_x + $x))
+                    x_2=$(($max_x - ($new_max_x - $point) - $x - $adj))
+                    offset_1=$((($y * $max_x) + $x_1))
+                    offset_2=$((($y * $max_x) + $x_2))
+                    if [ $x_1 -lt 0 ]; then
+                        offset_1=$offset_2
+                    fi
+                    if [ $x_2 -ge $max_x  ]; then
+                        offset_2=$offset_1
+                    fi
+                    new_map+=("$dot")
+                    new_offset=$((($y * $new_max_x) + $x))
+                    new_map[$new_offset]=$((${map[$offset_1]} | ${map[$offset_2]}))
+                done
+            done
+            map=("${new_map[@]}")
+            max_x=$new_max_x
+            ;;
+        y)
+            local new_max_y=$(($max_y - $point - 1))
+            if [ $point -gt $new_max_y ]; then
+                new_max_y=$point
+            fi
+            local adj=$((max_y % 2))
+            for (( y=0; y<$new_max_y; y++ )); do
+                # do the y offsets here
+                y_1=$(($point - $new_max_y + $y))
+                y_2=$(($max_y - ($new_max_y - $point) - $y - $adj))
+                offset_1=$(($y_1 * $max_x))
+                offset_2=$(($y_2 * $max_x))
+                if [ $y_1 -lt 0 ]; then
+                    offset_1=$offset_2
+                fi
+                if [ $y_2 -ge $max_y  ]; then
+                    offset_2=$offset_1
+                fi
+                for (( x=0; x<$max_x; x++ )); do
+                    off_1=$(($offset_1+$x))
+                    off_2=$(($offset_2+$x))
+                    new_map+=("$dot")
+                    new_offset=$((($y * $max_x) + $x))
+                    new_map[$new_offset]=$((${map[$off_1]} | ${map[$off_2]}))
+                done
+            done
+            map=("${new_map[@]}")
+            max_y=$new_max_y
+            ;;
+    esac
+}
+
+get_points_count() {
+    local count=0
+    for point in "${map[@]}"; do
+        ((count+=$point))
+    done
+
+    echo $count
+}
+
+#display_map
+
+# do first fold
+fold "${folds[0]}"
+echo
+#display_map
+echo
+echo "There are $(get_points_count) dots visible after first fold"
+for (( f=1; f<${#folds[@]}; f++ )); do
+    echo "Doing fold $((f+1)) of ${#folds[@]}"
+    fold "${folds[$f]}"
+done
+echo
+echo "After all folds:"
+display_map
diff --git a/day13/input.txt b/day13/input.txt
new file mode 100644
index 0000000..4007274
--- /dev/null
+++ b/day13/input.txt
@@ -0,0 +1,892 @@
+604,512
+8,675
+621,465
+172,851
+1205,212
+443,366
+817,728
+795,155
+788,334
+89,257
+693,56
+1091,459
+363,145
+1029,268
+1230,89
+692,418
+485,584
+299,138
+1113,630
+817,166
+142,123
+1238,226
+1295,74
+689,877
+1133,880
+37,504
+925,274
+1178,169
+493,728
+949,689
+708,810
+698,697
+187,662
+348,619
+537,794
+161,511
+773,324
+177,686
+282,695
+756,778
+440,856
+1093,530
+1039,376
+313,350
+1184,807
+78,383
+701,514
+303,802
+1222,707
+363,141
+1163,631
+575,854
+452,305
+900,726
+272,786
+1061,771
+167,26
+249,771
+403,248
+1257,82
+557,380
+1149,847
+402,103
+694,254
+832,390
+1285,467
+154,695
+689,316
+894,441
+273,586
+382,786
+408,469
+385,521
+443,814
+765,810
+435,459
+433,802
+788,281
+308,374
+746,759
+411,406
+392,553
+882,648
+679,92
+947,476
+537,793
+771,617
+858,645
+343,372
+383,690
+416,707
+477,583
+1202,264
+396,679
+1235,646
+353,431
+1211,75
+54,238
+992,675
+341,574
+1059,807
+27,138
+11,791
+8,786
+632,588
+756,38
+741,235
+97,319
+281,290
+643,103
+636,183
+189,157
+870,38
+426,761
+1202,854
+828,190
+460,564
+1304,665
+18,183
+525,712
+564,114
+1087,457
+721,290
+1064,693
+577,859
+20,99
+393,36
+1089,802
+1084,200
+303,214
+1,399
+68,439
+527,710
+177,208
+689,416
+351,354
+515,155
+117,705
+977,561
+177,462
+90,716
+877,92
+318,227
+631,792
+679,568
+418,262
+974,312
+395,794
+537,522
+756,784
+810,100
+1039,829
+671,871
+435,539
+564,850
+600,826
+994,274
+765,234
+771,737
+1061,123
+771,119
+771,605
+177,120
+130,402
+765,754
+714,115
+903,406
+609,514
+557,575
+617,838
+1240,620
+940,645
+928,70
+375,437
+1081,519
+894,187
+820,420
+648,229
+500,213
+564,626
+1195,169
+616,640
+607,462
+820,644
+691,74
+1193,548
+967,372
+45,185
+1043,213
+662,229
+728,668
+964,520
+1211,523
+850,184
+1287,715
+924,700
+843,662
+244,89
+1022,253
+758,568
+169,158
+23,49
+797,863
+426,329
+686,387
+817,831
+117,548
+1309,47
+996,747
+850,782
+137,796
+867,80
+1059,695
+100,486
+731,199
+1109,135
+306,296
+595,121
+236,632
+771,289
+18,711
+1066,168
+1156,695
+407,401
+959,456
+730,117
+306,828
+1004,63
+90,402
+83,488
+1289,714
+23,802
+267,681
+631,179
+992,358
+820,386
+646,716
+1079,682
+1203,646
+1133,871
+952,281
+711,1
+177,774
+679,886
+15,820
+318,667
+1178,729
+475,484
+1066,217
+102,344
+402,859
+679,267
+1285,543
+137,768
+1287,845
+383,513
+1,847
+534,408
+358,723
+305,292
+997,234
+1245,858
+907,471
+1119,140
+874,812
+341,225
+55,893
+1309,847
+855,152
+1143,868
+1126,66
+277,24
+1001,259
+1056,868
+694,813
+935,742
+247,849
+74,565
+744,483
+396,7
+407,717
+1048,553
+525,182
+316,274
+867,432
+1236,777
+546,712
+1046,520
+812,217
+1231,168
+343,350
+13,772
+303,92
+517,332
+676,175
+296,169
+843,403
+567,322
+873,140
+246,425
+639,871
+689,116
+460,819
+587,87
+107,406
+572,756
+403,871
+115,92
+1133,774
+1017,465
+437,140
+907,23
+1220,492
+177,14
+1059,848
+1058,791
+1125,191
+596,563
+385,274
+843,120
+632,306
+1299,679
+952,723
+137,870
+1031,152
+783,184
+1091,248
+482,444
+132,784
+1228,280
+1071,238
+974,536
+1019,866
+805,96
+910,359
+1255,289
+701,185
+1153,512
+301,432
+1236,663
+261,156
+1004,598
+734,626
+1,280
+161,502
+786,380
+184,828
+1041,274
+1236,329
+254,754
+547,400
+339,791
+115,14
+995,103
+1303,749
+42,697
+743,535
+1099,316
+261,431
+185,191
+402,707
+528,306
+681,880
+679,438
+832,504
+884,565
+1113,354
+744,341
+566,859
+559,794
+907,572
+554,784
+488,532
+935,152
+65,858
+856,87
+505,798
+710,602
+694,640
+1255,513
+1037,308
+559,100
+353,15
+600,656
+744,553
+1285,796
+850,778
+870,158
+838,296
+828,704
+928,516
+202,697
+472,598
+710,656
+279,876
+421,439
+293,192
+567,238
+1,737
+1173,781
+761,130
+1123,344
+1120,544
+833,798
+398,620
+293,689
+631,438
+676,719
+129,890
+513,415
+823,26
+1205,606
+604,382
+1178,281
+694,81
+467,232
+997,350
+1248,206
+467,344
+1014,59
+505,759
+567,359
+1183,700
+370,645
+1236,117
+1223,656
+822,532
+554,38
+703,686
+1009,124
+817,511
+78,511
+545,84
+634,245
+241,659
+1069,659
+214,38
+370,598
+1138,450
+1108,697
+1037,138
+127,700
+554,110
+579,606
+416,187
+797,479
+343,522
+956,798
+1067,854
+1141,158
+900,805
+791,82
+259,382
+47,73
+218,40
+194,75
+1121,157
+221,64
+679,845
+1011,138
+261,599
+1287,49
+619,74
+711,449
+807,455
+12,0
+572,614
+1242,439
+386,700
+955,586
+1086,438
+75,870
+189,289
+1235,855
+576,511
+691,121
+1007,802
+1017,702
+1268,197
+1033,24
+490,698
+1181,788
+952,837
+200,588
+354,544
+997,561
+336,43
+211,513
+457,92
+1004,296
+527,742
+865,570
+756,106
+748,722
+1203,488
+1243,38
+907,871
+1183,262
+403,471
+728,444
+493,495
+691,522
+728,450
+520,672
+254,868
+751,794
+788,371
+493,502
+227,371
+928,108
+1160,838
+782,535
+957,124
+50,606
+967,522
+336,704
+400,535
+537,101
+984,172
+1248,598
+914,679
+190,544
+710,82
+443,65
+1022,254
+301,837
+221,610
+833,23
+546,182
+788,262
+960,754
+423,660
+150,390
+443,829
+269,821
+201,759
+724,455
+102,120
+1011,756
+489,728
+947,418
+221,830
+554,486
+8,451
+1064,245
+100,110
+996,595
+1039,669
+1047,259
+487,868
+865,324
+293,205
+679,456
+23,214
+763,435
+306,63
+59,121
+127,38
+764,182
+313,234
+485,830
+853,452
+566,341
+172,127
+1178,277
+1208,438
+343,126
+957,15
+366,193
+547,696
+1228,614
+730,483
+293,554
+525,802
+1297,772
+1298,0
+246,21
+545,810
+894,453
+1298,371
+219,248
+1220,402
+927,445
+671,522
+853,92
+843,491
+612,25
+656,620
+196,156
+318,536
+130,514
+8,108
+1180,402
+440,606
+1049,156
+7,593
+1256,292
+735,854
+105,10
+231,682
+607,208
+884,313
+1220,403
+1063,401
+706,382
+631,326
+482,767
+539,617
+172,319
+952,169
+703,462
+469,191
+219,808
+870,856
+790,672
+177,583
+90,178
+627,756
+177,880
+1309,280
+1238,318
+74,329
+90,492
+621,877
+127,856
+773,122
+430,886
+1156,491
+1116,184
+803,183
+971,791
+1101,820
+908,859
+631,715
+825,830
+336,268
+1265,521
+728,278
+44,642
+935,16
+902,693
+825,310
+689,702
+336,88
+982,274
+364,418
+485,64
+172,892
+621,712
+261,208
+382,516
+867,428
+1287,802
+833,871
+67,807
+321,472
+1289,703
+355,586
+760,331
+748,274
+771,80
+821,728
+924,252
+75,855
+657,157
+1141,360
+959,386
+797,415
+271,376
+1049,208
+343,768
+1280,619
+385,373
+55,737
+92,722
+80,469
+1138,2
+1039,630
+172,767
+671,74
+806,523
+686,448
+346,520
+1089,64
+853,540
+251,198
+674,183
+582,26
+1109,56
+88,707
+354,798
+545,754
+865,74
+1178,784
+681,351
+607,686
+228,313
+1061,571
+624,387
+753,380
+25,427
+1183,632
+1138,127
+263,635
+1009,431
+810,213
+135,812
+35,474
+45,290
+947,28
+221,150
+1002,744
+736,469
+23,845
+679,326
+1257,812
+1058,859
+969,359
+72,226
+457,353
+786,514
+75,407
+1061,323
+460,75
+616,254
+1133,462
+201,56
+835,186
+132,617
+746,856
+714,779
+833,583
+865,77
+710,238
+1034,830
+537,324
+309,259
+373,268
+30,617
+1193,820
+25,602
+1146,386
+59,773
+1009,462
+1274,418
+492,834
+609,521
+460,782
+271,513
+718,296
+83,264
+1287,92
+129,182
+79,168
+862,645
+428,694
+478,728
+771,277
+375,152
+348,828
+428,246
+753,319
+469,703
+313,561
+903,717
+1238,588
+1260,382
+1042,252
+358,169
+539,119
+928,826
+353,770
+318,675
+358,281
+565,637
+161,390
+597,184
+587,38
+817,495
+975,301
+1039,14
+1019,476
+47,885
+1113,4
+219,459
+244,168
+18,631
+785,802
+308,520
+247,269
+992,667
+907,696
+920,330
+440,494
+547,435
+1131,708
+631,568
+271,883
+77,859
+1123,662
+288,254
+306,619
+607,14
+678,588
+191,306
+664,178
+80,362
+132,611
+1180,514
+1175,812
+20,795
+1099,80
+572,726
+1064,201
+850,564
+282,247
+1096,38
+50,512
+547,98
+1208,344
+226,591
+1289,479
+92,274
+1173,796
+1110,306
+358,725
+1232,383
+18,318
+619,522
+654,620
+664,268
+967,544
+621,778
+132,731
+803,260
+1028,112
+788,632
+82,166
+1210,486
+281,77
+75,646
+579,199
+97,823
+653,399
+580,665
+974,43
+547,494
+674,711
+1230,425
+313,544
+477,311
+753,823
+117,189
+765,140
+27,318
+599,1
+600,292
+884,761
+1138,892
+903,269
+600,82
+999,372
+621,30
+571,264
+877,130
+677,31
+89,637
+1114,156
+12,448
+108,630
+375,742
+736,89
+873,364
+88,35
+566,61
+862,249
+935,437
+788,523
+783,866
+
+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