solve day 6 (with maths)

2023/day05_almanac.go

@@ -0,0 +1,188 @@
+package _023
+
+import (
+	"bufio"
+	"io"
+	"slices"
+	"strings"
+)
+
+func Day05Part1(input io.Reader) (int, error) {
+	scanner := bufio.NewScanner(input)
+
+	scanner.Scan()
+	seeds := lineToInts(strings.TrimPrefix(scanner.Text(), "seeds: "))
+
+	scanner.Scan()
+
+	inMap := false
+	var currentMap day05Map
+	for scanner.Scan() {
+		line := scanner.Text()
+		if line == "" {
+			for i, seed := range seeds {
+				seeds[i] = currentMap.convert(seed)
+			}
+			inMap = false
+			currentMap = nil
+		} else if strings.HasSuffix(line, "map:") {
+			inMap = true
+		} else if inMap {
+			currentMap = append(currentMap, newDay05Range(line))
+		}
+	}
+
+	if inMap {
+		// Convert one last time if necessary
+		for i, seed := range seeds {
+			seeds[i] = currentMap.convert(seed)
+		}
+	}
+
+	return slices.Min(seeds), nil
+}
+
+func Day05Part2(input io.Reader) (int, error) {
+	scanner := bufio.NewScanner(input)
+
+	scanner.Scan()
+	seedRanges := parseSeedRanges(lineToInts(strings.TrimPrefix(scanner.Text(), "seeds: ")))
+
+	scanner.Scan()
+
+	inMap := false
+	var currentMap day05Map
+	for scanner.Scan() {
+		line := scanner.Text()
+		if line == "" {
+			var newRanges []day05SeedRange
+			for _, sRange := range seedRanges {
+				newRanges = append(newRanges, currentMap.convertRange(sRange)...)
+			}
+			seedRanges = newRanges
+			inMap = false
+			currentMap = nil
+		} else if strings.HasSuffix(line, "map:") {
+			inMap = true
+		} else if inMap {
+			currentMap = append(currentMap, newDay05Range(line))
+		}
+	}
+
+	if inMap {
+		// Convert one last time if necessary
+		var newRanges []day05SeedRange
+		for _, sRange := range seedRanges {
+			newRanges = append(newRanges, currentMap.convertRange(sRange)...)
+		}
+		seedRanges = newRanges
+		inMap = false
+		currentMap = nil
+	}
+
+	mini := int(^uint(0) >> 1) // highest int
+	for _, r := range seedRanges {
+		if r.start < mini {
+			mini = r.start
+		}
+	}
+
+	return mini, nil
+}
+
+func parseSeedRanges(ints []int) []day05SeedRange {
+	ranges := make([]day05SeedRange, len(ints)/2)
+	for i := 0; i < len(ints)-1; i += 2 {
+		ranges[i/2] = day05SeedRange{start: ints[i], end: ints[i] + ints[i+1]}
+	}
+	return ranges
+}
+
+// range is [start; end)
+// start is included, end is not.
+type day05SeedRange struct {
+	start, end int
+}
+
+type day05Range struct {
+	destStart, sourceStart, length int
+}
+
+func newDay05Range(line string) day05Range {
+	ints := lineToInts(line)
+	return day05Range{
+		destStart:   ints[0],
+		sourceStart: ints[1],
+		length:      ints[2],
+	}
+}
+
+func (r day05Range) sourceEnd() int {
+	return r.sourceStart + r.length
+}
+
+func (r day05Range) destEnd() int {
+	return r.destStart + r.length
+}
+
+func (r day05Range) convert(n int) (int, bool) {
+	if n >= r.sourceStart && n < r.sourceEnd() {
+		return r.mustConvert(n), true
+	}
+	return n, false
+}
+
+func (r day05Range) mustConvert(n int) int {
+	return n - r.sourceStart + r.destStart
+}
+
+func (r day05Range) convertRange(s day05SeedRange) (converted []day05SeedRange, notConverted []day05SeedRange) {
+	if r.sourceStart <= s.start && s.end <= r.sourceEnd() {
+		//   s-----s
+		// r--------r
+		return []day05SeedRange{{start: r.mustConvert(s.start), end: r.mustConvert(s.end)}}, nil
+	} else if s.start < r.sourceStart && r.sourceStart <= s.end && s.end <= r.sourceEnd() {
+		// s-------s
+		//    r--------r
+		return []day05SeedRange{{start: r.destStart, end: r.mustConvert(s.end)}}, []day05SeedRange{{start: s.start, end: r.sourceStart}}
+	} else if r.sourceStart <= s.start && s.start <= r.sourceEnd() && r.sourceEnd() < s.end {
+		//    s-------s
+		// r--------r
+		return []day05SeedRange{{start: r.mustConvert(s.start), end: r.destEnd()}}, []day05SeedRange{{start: r.sourceEnd(), end: s.end}}
+	} else if s.start <= r.sourceStart && r.sourceEnd() < s.end {
+		// s------------s
+		//   r--------r
+		return []day05SeedRange{{start: r.destStart, end: r.destEnd()}}, []day05SeedRange{{start: s.start, end: r.sourceStart}, {start: r.sourceEnd(), end: s.end}}
+	} else {
+		// s---s
+		//        r-----r
+		return nil, []day05SeedRange{s}
+	}
+}
+
+type day05Map []day05Range
+
+func (m day05Map) convert(n int) int {
+	for _, dRange := range m {
+		if conv, ok := dRange.convert(n); ok {
+			return conv
+		}
+	}
+	return n
+}
+
+func (m day05Map) convertRange(s day05SeedRange) []day05SeedRange {
+	var converted []day05SeedRange
+	toConvert := []day05SeedRange{s}
+	for _, dRange := range m {
+		var toConvertNext []day05SeedRange
+		for _, c := range toConvert {
+			var conv []day05SeedRange
+			conv, toConvertNext = dRange.convertRange(c)
+			converted = append(converted, conv...)
+		}
+		toConvert = toConvertNext
+	}
+	converted = append(converted, toConvert...)
+	return converted
+}

2023/day05_almanac_test.go

@@ -0,0 +1,63 @@
+package _023
+
+import (
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"os"
+	"testing"
+)
+
+func TestDay05Part1(t *testing.T) {
+	tests := []testCase{
+		{"inputs/day05_test1", 1},
+		{"inputs/day05", 227653707},
+	}
+	for _, test := range tests {
+		t.Run(test.filename, check(test, Day05Part1))
+	}
+	t.Run("inputs/day05", func(t *testing.T) {
+		file, err := os.Open("inputs/day05")
+		require.NoError(t, err)
+		got, err := Day05Part1(file)
+		require.NoError(t, err)
+		assert.Less(t, got, 392296326) // 392296326 is too high
+	})
+}
+
+func TestDay05Part2(t *testing.T) {
+	tests := []testCase{
+		{"inputs/day05_test2", 46},
+		{"inputs/day05", 78775051},
+	}
+	for _, test := range tests {
+		t.Run(test.filename, check(test, Day05Part2))
+	}
+}
+
+func TestDay05Ranges(t *testing.T) {
+	tests := []struct {
+		name      string
+		dRange    day05Range
+		seedRange day05SeedRange
+		expected  []day05SeedRange
+	}{
+		{
+			"seed included in range",
+			day05Range{0, 5, 5},
+			day05SeedRange{6, 8},
+			[]day05SeedRange{{1, 3}},
+		},
+		{
+			"range included in seed",
+			day05Range{0, 10, 2},
+			day05SeedRange{9, 13},
+			[]day05SeedRange{{0, 2}, {9, 10}, {12, 13}},
+		},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			got := day05Map{test.dRange}.convertRange(test.seedRange)
+			assert.Equal(t, test.expected, got)
+		})
+	}
+}

2023/day06_boats.go

@@ -0,0 +1,63 @@
+package _023
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"math"
+	"strings"
+)
+
+func Day06Part1(input io.Reader) (int, error) {
+	scanner := bufio.NewScanner(input)
+
+	scanner.Scan()
+	times := lineToInts(strings.TrimPrefix(scanner.Text(), "Time:"))
+	scanner.Scan()
+	distances := lineToInts(strings.TrimPrefix(scanner.Text(), "Distance:"))
+	fmt.Println(times, distances)
+
+	margin := 1
+
+	for i := 0; i < len(times); i++ {
+		x1, x2 := zeros(times[i], distances[i])
+		if distance(x1, times[i]) <= distances[i] {
+			x1++
+		}
+		margin *= x2 - x1
+	}
+
+	return margin, nil
+}
+
+func zeros(time, distance int) (int, int) {
+	t, d := float64(time), float64(distance)
+	delta := math.Sqrt(math.Pow(t, 2) - 4*d)
+	return int(math.Ceil((t - delta) / 2)), int(math.Ceil((t + delta) / 2))
+}
+
+func distance(timePress, timeMax int) int {
+	return timePress * (timeMax - timePress)
+}
+
+func Day06Part2(input io.Reader) (int, error) {
+	scanner := bufio.NewScanner(input)
+
+	scanner.Scan()
+	times := lineToInts(strings.ReplaceAll(strings.TrimPrefix(scanner.Text(), "Time:"), " ", ""))
+	scanner.Scan()
+	distances := lineToInts(strings.ReplaceAll(strings.TrimPrefix(scanner.Text(), "Distance:"), " ", ""))
+	fmt.Println(times, distances)
+
+	margin := 1
+
+	for i := 0; i < len(times); i++ {
+		x1, x2 := zeros(times[i], distances[i])
+		if distance(x1, times[i]) <= distances[i] {
+			x1++
+		}
+		margin *= x2 - x1
+	}
+
+	return margin, nil
+}

2023/day06_boats_test.go

@@ -0,0 +1,25 @@
+package _023
+
+import (
+	"testing"
+)
+
+func TestDay06Part1(t *testing.T) {
+	tests := []testCase{
+		{"inputs/day06_test1", 288},
+		{"inputs/day06", 1660968},
+	}
+	for _, test := range tests {
+		t.Run(test.filename, check(test, Day06Part1))
+	}
+}
+
+func TestDay06Part2(t *testing.T) {
+	tests := []testCase{
+		{"inputs/day06_test1", 71503},
+		{"inputs/day06", 26499773},
+	}
+	for _, test := range tests {
+		t.Run(test.filename, check(test, Day06Part2))
+	}
+}

2023/inputs/day05

@@ -0,0 +1,236 @@
+seeds: 2880930400 17599561 549922357 200746426 1378552684 43534336 155057073 56546377 824205101 378503603 1678376802 130912435 2685513694 137778160 2492361384 188575752 3139914842 1092214826 2989476473 58874625
+
+seed-to-soil map:
+341680072 47360832 98093750
+1677587229 1836834678 160297919
+1122651749 4014790961 280176335
+2279929873 2689269992 53644948
+3916120104 1199400457 172302726
+0 381576527 58197295
+1402828084 3450816018 274759145
+3909949227 2540063154 6170877
+802918801 2384227172 155835982
+4088422830 3244271552 206544466
+958754783 1997132597 28874650
+58197295 306349987 75226540
+180784667 145454582 160895405
+2334903647 1543332738 293501940
+3699983017 2997982209 25342830
+2333574821 2687941166 1328826
+3111317969 1371703183 171629555
+2806959198 2135774873 248452299
+2766721604 717118138 40237594
+3055411497 2632034694 55906472
+2628405587 3023325039 138316017
+1837885148 757355732 442044725
+3725325847 2813358829 184623380
+3353391413 2026007247 109767626
+987629433 3962399141 10015813
+717118138 2546234031 85800663
+3282947524 2742914940 70443889
+1080275742 3972414954 42376007
+133423835 0 47360832
+3463159039 3725575163 236823978
+997645246 3161641056 82630496
+
+soil-to-fertilizer map:
+303672059 1087423328 103502353
+171922589 2907629744 91556518
+2064217168 468859004 91214014
+1129888530 1046445685 40977643
+3698610046 4215442249 79525047
+1045870106 1586657152 41455160
+1170866173 1322928302 17679660
+4160148003 3332238470 107558461
+4267706464 3853049576 27260832
+0 3007612896 90771201
+3447204990 3880310408 249339913
+1189561657 1438888401 43309463
+4019710828 3219712242 104981462
+2226263856 2187322171 114088350
+553216166 1847338068 182148047
+3217647099 3439796931 229557891
+2832115692 1482197864 23307900
+867366834 94995931 178503272
+1969221237 0 94995931
+3785679859 3704810535 148239041
+1095751900 2693816297 34136630
+4124692290 3669354822 35455713
+454935727 1340607962 98280439
+2204466075 1628112312 21797781
+1947833351 2164918461 21387886
+2634687717 1649910093 197427975
+263479107 2850768768 40192952
+3696544903 3217647099 2065143
+735364213 1190925681 132002621
+3050783393 2337205982 47600704
+1087325266 2999186262 8426634
+3778135093 3324693704 7544766
+2855423592 273499203 195359801
+90771201 1505505764 81151388
+2340352206 560073018 290906919
+1531641800 939263745 107181940
+1188545833 2186306347 1015824
+1355686961 850979937 88283808
+1492181516 2029486115 39460284
+1638823740 2384806686 309009611
+2155431182 2894390312 13239432
+1443970769 2068946399 48210747
+1232871120 2727952927 122815841
+3933918900 4129650321 85791928
+2631259125 2890961720 3428592
+407174412 2117157146 47761315
+2168670614 2301410521 35795461
+
+fertilizer-to-water map:
+4253126168 3603943470 41841128
+3150812716 3873122781 161556325
+4132148538 3445929121 16652907
+4071215062 2557593856 10373731
+3585414898 2401284809 61555959
+124617758 989226185 56063423
+1311995731 916233018 72993167
+180681181 891200267 25032751
+1577315548 1448436684 231921083
+69948934 1391916079 39397864
+2730663795 3577458422 26485048
+2453473122 3255362867 102306532
+4148801445 3801350502 12292818
+3002725397 3107275548 148087319
+3525935437 3813643320 59479461
+3982955340 3357669399 88259722
+2631712351 2567967587 98951444
+628324302 2038793089 109830184
+3427245435 3721480891 3936914
+796140554 1045289608 36965524
+939693576 1140241200 24301167
+205713932 1680357767 358435322
+4161094263 2666919031 92031905
+1103981621 0 206162329
+1809236631 761213122 129987145
+1310143950 1431313943 1851781
+4081588793 3056715803 50559745
+738154486 1082255132 57986068
+564149254 206162329 64175048
+3722667150 4034679106 260288190
+3431182349 2462840768 94753088
+109346798 1433165724 15270960
+2757148843 2811139249 245576554
+1044349135 2294919620 59632486
+833106078 270337377 106587498
+3646970857 3645784598 75696293
+0 2354552106 4006979
+1974270838 376924875 384288247
+3312369041 3462582028 114876394
+2401284809 2758950936 52188313
+1384988898 1199589429 192326650
+963994743 2214565228 80354392
+1939223776 1164542367 35047062
+4006979 2148623273 65941955
+2555779654 3725417805 75932697
+
+water-to-light map:
+1553071310 2767299260 81555093
+1638385137 3758734 7165416
+3923895602 3742459208 355646104
+2563492152 40550035 317968
+357175543 151852464 53516575
+756535305 2730597762 36701498
+1142337672 1915537677 164067723
+436470886 2848854353 61956232
+1316538987 1679005354 102639946
+609765571 2079605400 146769734
+1306405395 2660382036 10133592
+3817572860 3406157555 106322742
+2023184953 353497588 62195869
+3531543848 4223491605 71475691
+410692118 126073696 25778768
+4279541706 3727562743 14896465
+2903607795 1495097536 74179449
+1794747312 2279656479 95385933
+2783150325 2269091374 10565105
+3406157555 4098105312 125386293
+2145462956 205369039 148128549
+2833741244 2401175172 69866551
+793236803 685594104 306384629
+1645550553 2511185277 149196759
+1419178933 1781645300 133892377
+1634626403 0 3758734
+3274934245 2471041723 36449164
+0 1097896179 357175543
+2563810120 991978733 105917446
+4294438171 3727033618 529125
+2688189328 1569276985 94960997
+2669727566 2507490887 3694390
+3311383409 10924150 29625885
+1099621432 2226375134 42716240
+1890133245 2910810585 133051708
+583632811 2375042412 26132760
+498427118 40868003 85205693
+2293591505 415693457 269900647
+2673421956 1664237982 14767372
+2085380822 2670515628 60082134
+3603019539 3512480297 214553321
+2977787244 3043862293 297147001
+2793715430 1455071722 40025814
+
+light-to-temperature map:
+3752181853 3850028427 61847460
+3392702182 4061054452 68370555
+3610251302 4129425007 141930551
+2019529001 2633762146 55812503
+1423059901 2612524947 21237199
+1637625157 3160312690 128493598
+2109055159 2018596226 368399035
+343891384 811352094 920120231
+154347384 2422980947 189544000
+2075341504 1978947609 33713655
+1444297100 2966984633 193328057
+35985686 2689574649 118361698
+2477454194 0 811352094
+1772053717 1854798742 124148867
+1264011615 2807936347 159048286
+0 2386995261 35985686
+1766118755 2012661264 5934962
+3814029313 3392702182 457326245
+3461072737 3911875887 149178565
+1896202584 1731472325 123326417
+
+temperature-to-humidity map:
+3344602117 2991074372 262457649
+1707309180 3911386116 383581180
+3778482785 2130995124 374719434
+3607059766 3253532021 171423019
+584508486 478912361 161371970
+1578590582 2505714558 128718598
+3294145751 1806488186 50456366
+1143023241 2829557603 161516769
+1304540010 1856944552 274050572
+2090890360 3424955040 344665999
+2435556359 1143023241 663464945
+496214964 1000471163 88293522
+0 640284331 360186832
+3099021304 2634433156 195124447
+360186832 342884229 136028132
+745880456 0 342884229
+4153202219 3769621039 141765077
+
+humidity-to-location map:
+3114211644 984440400 35385940
+3530465412 479339778 128291026
+0 3699707734 285474938
+2898087648 3606829306 92878428
+2762235329 607630804 135852319
+4210792153 4197161772 84175143
+3149597584 31394121 380867828
+1848709689 0 31394121
+1880103810 412261949 67077829
+285474938 1579019790 1563234751
+2990966076 3566305423 40523883
+2434079297 1019826340 328156032
+2371232521 3985182672 62846776
+1947181639 3142254541 424050882
+3899713715 1347982372 148315733
+3031489959 1496298105 82721685
+4197161772 4281336915 13630381
+3658756438 743483123 240957277

2023/inputs/day05_test1

@@ -0,0 +1,34 @@
+seeds: 79 14 55 13
+
+seed-to-soil map:
+50 98 2
+52 50 48
+
+soil-to-fertilizer map:
+0 15 37
+37 52 2
+39 0 15
+
+fertilizer-to-water map:
+49 53 8
+0 11 42
+42 0 7
+57 7 4
+
+water-to-light map:
+88 18 7
+18 25 70
+
+light-to-temperature map:
+45 77 23
+81 45 19
+68 64 13
+
+temperature-to-humidity map:
+0 69 1
+1 0 69
+
+humidity-to-location map:
+60 56 37
+56 93 4
+1 35 1

2023/inputs/day05_test2

@@ -0,0 +1,33 @@
+seeds: 79 14 55 13
+
+seed-to-soil map:
+50 98 2
+52 50 48
+
+soil-to-fertilizer map:
+0 15 37
+37 52 2
+39 0 15
+
+fertilizer-to-water map:
+49 53 8
+0 11 42
+42 0 7
+57 7 4
+
+water-to-light map:
+88 18 7
+18 25 70
+
+light-to-temperature map:
+45 77 23
+81 45 19
+68 64 13
+
+temperature-to-humidity map:
+0 69 1
+1 0 69
+
+humidity-to-location map:
+60 56 37
+56 93 4

2023/inputs/day06

@@ -0,0 +1,2 @@
+Time:        47     98     66     98
+Distance:   400   1213   1011   1540

2023/inputs/day06_test1

@@ -0,0 +1,2 @@
+Time:      7  15   30
+Distance:  9  40  200

2023/lib.go

@@ -0,0 +1,23 @@
+package _023
+
+import (
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+var reg = regexp.MustCompile(`\s+`)
+
+func lineToInts(line string) []int {
+	line = strings.TrimSpace(line)
+	values := reg.Split(line, -1)
+	ints := make([]int, len(values))
+	for i, value := range values {
+		number, err := strconv.Atoi(value)
+		if err != nil {
+			panic(err)
+		}
+		ints[i] = number
+	}
+	return ints
+}