105 lines
1.8 KiB
Go
105 lines
1.8 KiB
Go
package twentythree
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import (
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"fmt"
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"strconv"
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)
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type game struct {
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cups []int
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currentCup int
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highestCup int
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}
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func (g *game) load(input string) error {
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for _, c := range input {
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cupNumber, err := strconv.Atoi(string(c))
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if err != nil {
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return err
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}
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if cupNumber > g.highestCup {
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g.highestCup = cupNumber
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}
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g.cups = append(g.cups, cupNumber)
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}
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if len(g.cups) > 0 {
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g.currentCup = g.cups[0]
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}
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return nil
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}
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func (g *game) play(moves int) string {
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for i := 0; i < moves; i++ {
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// pickup cups
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pickup := g.cups[1:4]
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remaining := []int{g.cups[0]}
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remaining = append(remaining, g.cups[4:]...)
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g.cups = remaining
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// find destination cup
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destination := false
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destinationIndex := -1
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t := g.currentCup - 1
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for !destination {
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if t <= 0 {
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t = g.highestCup
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}
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for i := 1; i < len(g.cups); i++ {
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if g.cups[i] == t {
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destinationIndex = i
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break
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}
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}
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if destinationIndex != -1 {
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destination = true
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}
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t--
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}
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// place cups
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newOrder := []int{}
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for _, c := range remaining[:destinationIndex+1] {
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newOrder = append(newOrder, c)
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}
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newOrder = append(newOrder, pickup...)
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for _, c := range remaining[destinationIndex+1:] {
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newOrder = append(newOrder, c)
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}
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g.cups = newOrder
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// Update current cup
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g.cups = g.cups[1:]
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g.cups = append(g.cups, g.currentCup)
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g.currentCup = g.cups[0]
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}
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return g.output()
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}
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func (g *game) output() string {
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state := []int{}
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for i, c := range g.cups {
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if c == 1 {
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state = append(state, g.cups[i+1:]...)
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state = append(state, g.cups[:i]...)
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}
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}
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output := ""
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for _, n := range state {
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output += fmt.Sprintf("%d", n)
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}
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return output
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}
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// PartOne What are the labels on the cups after cup 1
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func PartOne() string {
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g := game{}
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g.load("418976235")
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return g.play(100)
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}
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