Day 14 solution
This one's part 1 destroyed me. I had a very difficult time, trying 3 separate approaches, each one of which worked for most cases but eventually fell apart on the 5th sample or my actual puzzle input. I ended up reading a bunch of hints from the subreddit which eventually led me to a blog post describing this solution, which wasn't far off from what I had, but I was overcomplicating things. Part 2 surprised me in that I expected a simple "ore available divided by ore needed for 1 fuel" would solve it, but of course the excess chemicals produced in any given reaction meant that it wasn't that simple. So this approach uses that estimate as a lower bound, since it always underestimates, and then bisects its way to the solution (starting at the lower bound and adding 1 each time took too long). I'm sure a smarter upper bound choice could lower the runtime of this by a bit, but runtime isn't bad enough right now for me to try any additional optimizations.
This commit is contained in:
129
days/14.go
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129
days/14.go
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@ -0,0 +1,129 @@
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package days
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import (
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"fmt"
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"math"
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"strconv"
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"strings"
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u "parnic.com/aoc2019/utilities"
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)
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type reaction struct {
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inputs map[string]int64
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output u.Pair[string, int]
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}
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type Day14 struct {
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reactions []reaction
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}
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func (d *Day14) Parse() {
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lines := u.GetStringLines("14p")
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d.reactions = make([]reaction, len(lines))
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for i, line := range lines {
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sides := strings.Split(line, " => ")
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inputs := strings.Split(sides[0], ", ")
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output := sides[1]
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outPair := strings.Split(output, " ")
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outAmt, _ := strconv.Atoi(outPair[0])
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d.reactions[i].output = u.Pair[string, int]{First: outPair[1], Second: outAmt}
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d.reactions[i].inputs = make(map[string]int64)
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for _, input := range inputs {
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pair := strings.Split(input, " ")
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d.reactions[i].inputs[pair[1]], _ = strconv.ParseInt(pair[0], 10, 64)
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}
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}
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}
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func (d Day14) getReactionProducing(chem string) *reaction {
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for _, reaction := range d.reactions {
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if reaction.output.First == chem {
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return &reaction
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}
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}
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return nil
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}
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func (d Day14) Num() int {
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return 14
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}
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func (d *Day14) getOreRequiredForFuel(qty int64) int64 {
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oreRequired := int64(0)
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needs := map[string]int64{
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"FUEL": qty,
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}
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excess := make(map[string]int64)
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getFromExcess := func(qty int64, chemical string) int64 {
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available := u.Min(excess[chemical], qty)
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excess[chemical] -= available
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return available
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}
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for len(needs) > 0 {
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keys := u.MapKeys(needs)
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producing := keys[0]
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qtyRequired := needs[producing]
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delete(needs, producing)
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fromExcess := getFromExcess(qtyRequired, producing)
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if fromExcess == qtyRequired {
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continue
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}
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qtyRequired -= fromExcess
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reaction := d.getReactionProducing(producing)
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qtyProduced := int64(reaction.output.Second)
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reactionsNeeded := int64(math.Ceil(float64(qtyRequired) / float64(qtyProduced)))
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excess[producing] = (qtyProduced * reactionsNeeded) - qtyRequired
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for reagent, inputQty := range reaction.inputs {
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qtyNeeded := inputQty * reactionsNeeded
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if reagent == "ORE" {
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oreRequired += qtyNeeded
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} else {
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needs[reagent] += qtyNeeded
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}
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}
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}
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return oreRequired
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}
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func (d *Day14) Part1() string {
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neededOre := d.getOreRequiredForFuel(1)
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return fmt.Sprintf("%s%d%s", u.TextBold, neededOre, u.TextReset)
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}
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func (d *Day14) Part2() string {
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oreAvailable := int64(1000000000000)
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estimate := oreAvailable / d.getOreRequiredForFuel(1)
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high := estimate * 2
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low := estimate
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lastSuccess := low
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lastFailure := high
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fuelProduced := low
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for math.Abs(float64(lastFailure-lastSuccess)) > 1 {
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oreConsumed := d.getOreRequiredForFuel(fuelProduced)
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adjustment := (lastFailure - lastSuccess) / 2
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if oreConsumed < oreAvailable {
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lastSuccess = fuelProduced
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} else {
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lastFailure = fuelProduced
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adjustment = -adjustment
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}
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fuelProduced += adjustment
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}
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return fmt.Sprintf("%s%d%s", u.TextBold, lastSuccess, u.TextReset)
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}
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56
inputs/14p.txt
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56
inputs/14p.txt
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@ -0,0 +1,56 @@
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6 WBVJ, 16 CDVNK => 2 PJBZT
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135 ORE => 8 MWDXJ
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27 NBRHT, 2 NSWK, 2 CMHMQ, 29 NFCB, 11 KNGJ, 12 MGCKC, 56 NHTKL, 7 WNFSV => 1 FUEL
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1 SFJFX, 3 MXNK => 4 NLSBZ
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2 PFKRW, 1 VXFRX, 22 QDJCL => 6 GBDG
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7 TSTF, 4 ZLJN => 7 DMWS
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5 KPCF, 1 DLMDJ, 1 FNWGH => 6 TSTF
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8 DTWKS, 1 GBDG => 4 CGZQ
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26 CNWZM, 4 KPCF => 3 DTWKS
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1 JVLHM, 7 DTWKS, 7 PJBZT => 8 MRPHV
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2 MWDXJ => 3 VHFPC
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1 WXNW, 6 PFKRW => 7 ZVGVP
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2 ZVGVP => 1 CMHMQ
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8 JVLHM, 11 XRKN, 1 HCGKZ => 8 CHZLX
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20 TSTF => 4 XDZMZ
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3 CMHMQ, 7 ZVGVP, 10 XRKN => 9 FNWGH
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12 HCGKZ, 4 NLSBZ, 15 RWRDP, 4 MRPHV, 31 KRDV, 6 PMXK, 2 NFVZ => 7 KNGJ
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1 TXZCM => 9 BMPJ
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2 ZFXQ => 3 NBRHT
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13 JVLHM, 1 VHFPC => 3 PBJPZ
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7 HCGKZ => 7 PMXK
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2 RWRDP, 3 VSTQ, 12 PMXK => 7 MXNK
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1 PJBZT, 3 QRSK => 1 KRDV
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1 MGCKC, 6 CMHMQ => 6 PQTVS
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1 TNHCS, 24 ZLJN => 4 RWRDP
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5 MWDXJ, 1 WXNW => 9 QBCLF
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1 ZFXQ, 1 DLMDJ => 4 DJXRM
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1 ZFXQ => 2 CNWZM
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1 KPCF => 6 ZXDVF
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2 MRPHV => 1 GSTG
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5 BMPJ, 2 ZLJN => 8 XQJZ
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1 MWDXJ, 1 ZVGVP => 3 CDVNK
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3 NFCB, 3 CMHMQ, 1 MWDXJ => 4 XRKN
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1 WXNW, 1 TXZCM => 5 ZLJN
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4 ZXDVF => 4 WBVJ
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2 GBDG => 4 KPCF
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4 CHZLX, 7 ZFXQ, 14 PQTVS => 9 VSTQ
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3 TXZCM, 7 ZLJN, 7 ZXDVF => 9 JVLHM
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1 DMWS, 3 TSTF => 5 HCGKZ
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2 CGZQ => 4 NFVZ
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2 PQTVS, 9 VMNJ => 9 TXZCM
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3 KPCF => 4 DLMDJ
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7 VMNJ, 24 XQJZ, 7 GSTG, 8 NLSBZ, 10 MGCKC, 2 SFJFX, 18 BMPJ => 1 NSWK
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41 CNWZM, 5 DJXRM, 1 QRSK, 1 KPCF, 15 XDZMZ, 3 MRPHV, 1 NLSBZ, 9 KRDV => 2 WNFSV
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10 PBJPZ, 29 BMPJ, 2 PMXK => 7 SFJFX
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116 ORE => 4 WXNW
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2 CNWZM => 2 TNHCS
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10 QBCLF => 7 NFCB
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1 QBCLF => 2 ZFXQ
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15 ZLJN => 7 QRSK
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183 ORE => 3 QDJCL
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11 GBDG => 5 VMNJ
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4 DMWS, 3 QRSK => 3 NHTKL
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124 ORE => 6 VXFRX
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1 MWDXJ => 6 MGCKC
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108 ORE => 9 PFKRW
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6
inputs/14s1.txt
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6
inputs/14s1.txt
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@ -0,0 +1,6 @@
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10 ORE => 10 A
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1 ORE => 1 B
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7 A, 1 B => 1 C
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7 A, 1 C => 1 D
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7 A, 1 D => 1 E
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7 A, 1 E => 1 FUEL
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7
inputs/14s2.txt
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7
inputs/14s2.txt
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9 ORE => 2 A
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8 ORE => 3 B
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7 ORE => 5 C
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3 A, 4 B => 1 AB
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5 B, 7 C => 1 BC
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4 C, 1 A => 1 CA
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2 AB, 3 BC, 4 CA => 1 FUEL
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9
inputs/14s3.txt
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9
inputs/14s3.txt
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@ -0,0 +1,9 @@
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157 ORE => 5 NZVS
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165 ORE => 6 DCFZ
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44 XJWVT, 5 KHKGT, 1 QDVJ, 29 NZVS, 9 GPVTF, 48 HKGWZ => 1 FUEL
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12 HKGWZ, 1 GPVTF, 8 PSHF => 9 QDVJ
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179 ORE => 7 PSHF
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177 ORE => 5 HKGWZ
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7 DCFZ, 7 PSHF => 2 XJWVT
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165 ORE => 2 GPVTF
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3 DCFZ, 7 NZVS, 5 HKGWZ, 10 PSHF => 8 KHKGT
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12
inputs/14s4.txt
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12
inputs/14s4.txt
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@ -0,0 +1,12 @@
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2 VPVL, 7 FWMGM, 2 CXFTF, 11 MNCFX => 1 STKFG
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17 NVRVD, 3 JNWZP => 8 VPVL
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53 STKFG, 6 MNCFX, 46 VJHF, 81 HVMC, 68 CXFTF, 25 GNMV => 1 FUEL
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22 VJHF, 37 MNCFX => 5 FWMGM
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139 ORE => 4 NVRVD
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144 ORE => 7 JNWZP
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5 MNCFX, 7 RFSQX, 2 FWMGM, 2 VPVL, 19 CXFTF => 3 HVMC
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5 VJHF, 7 MNCFX, 9 VPVL, 37 CXFTF => 6 GNMV
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145 ORE => 6 MNCFX
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1 NVRVD => 8 CXFTF
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1 VJHF, 6 MNCFX => 4 RFSQX
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176 ORE => 6 VJHF
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17
inputs/14s5.txt
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17
inputs/14s5.txt
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@ -0,0 +1,17 @@
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171 ORE => 8 CNZTR
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7 ZLQW, 3 BMBT, 9 XCVML, 26 XMNCP, 1 WPTQ, 2 MZWV, 1 RJRHP => 4 PLWSL
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114 ORE => 4 BHXH
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14 VRPVC => 6 BMBT
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6 BHXH, 18 KTJDG, 12 WPTQ, 7 PLWSL, 31 FHTLT, 37 ZDVW => 1 FUEL
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6 WPTQ, 2 BMBT, 8 ZLQW, 18 KTJDG, 1 XMNCP, 6 MZWV, 1 RJRHP => 6 FHTLT
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15 XDBXC, 2 LTCX, 1 VRPVC => 6 ZLQW
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13 WPTQ, 10 LTCX, 3 RJRHP, 14 XMNCP, 2 MZWV, 1 ZLQW => 1 ZDVW
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5 BMBT => 4 WPTQ
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189 ORE => 9 KTJDG
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1 MZWV, 17 XDBXC, 3 XCVML => 2 XMNCP
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12 VRPVC, 27 CNZTR => 2 XDBXC
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15 KTJDG, 12 BHXH => 5 XCVML
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3 BHXH, 2 VRPVC => 7 MZWV
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121 ORE => 7 VRPVC
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7 XCVML => 6 RJRHP
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5 BHXH, 4 VRPVC => 5 LTCX
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1
main.go
1
main.go
@ -44,6 +44,7 @@ var dayMap = []day{
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&days.Day11{},
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&days.Day12{},
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&days.Day13{},
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&days.Day14{},
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}
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func main() {
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17
utilities/map.go
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17
utilities/map.go
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@ -0,0 +1,17 @@
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package utilities
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func MapKeys[T comparable, U any](m map[T]U) []T {
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r := make([]T, 0, len(m))
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for k := range m {
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r = append(r, k)
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}
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return r
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}
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func MapValues[T comparable, U any](m map[T]U) []U {
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r := make([]U, 0, len(m))
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for _, v := range m {
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r = append(r, v)
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}
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return r
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}
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@ -1,5 +1,7 @@
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package utilities
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import "math"
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func GCD[T Integer](a, b T) T {
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if b == 0 {
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return a
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@ -25,3 +27,23 @@ func LCM[T Integer](nums ...T) uint64 {
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func lcm[T Integer](a, b T) uint64 {
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return uint64(a*b) / uint64(GCD(a, b))
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}
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func Min[T Number](nums ...T) T {
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numNums := len(nums)
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if numNums == 2 {
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return T(math.Min(float64(nums[0]), float64(nums[1])))
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}
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if numNums == 0 {
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return 0
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}
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least := nums[0]
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for i := 1; i < numNums; i++ {
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if nums[i] < least {
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least = nums[i]
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}
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}
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return least
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}
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Reference in New Issue
Block a user