91 lines
1.5 KiB
Go
91 lines
1.5 KiB
Go
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package main
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import (
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"bufio"
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_ "embed"
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"fmt"
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"strconv"
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"strings"
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aoc "go.sour.is/advent-of-code"
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"golang.org/x/exp/maps"
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)
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// var log = aoc.Log
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func main() { aoc.MustResult(aoc.Runner(run)) }
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type result struct {
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valuePT1 int
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valuePT2 int
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}
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func (r result) String() string { return fmt.Sprintf("%#v", r) }
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func run(scan *bufio.Scanner) (*result, error) {
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var vecsPT1 []aoc.Vector
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var vecsPT2 []aoc.Vector
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for scan.Scan() {
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text := scan.Text()
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if len(text) == 0 {
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continue
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}
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v, color := fromLine(text)
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vecsPT1 = append(vecsPT1, v)
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vecsPT2 = append(vecsPT2, fromColor(color))
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}
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return &result{
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valuePT1: findArea(vecsPT1),
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valuePT2: findArea(vecsPT2),
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}, nil
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}
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var OFFSET = map[string]aoc.Point{
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"R": {0, 1},
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"D": {1, 0},
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"L": {0, -1},
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"U": {-1, 0},
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}
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var OFFSET_INDEXES = maps.Values(OFFSET)
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func fromLine(text string) (aoc.Vector, string) {
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v := aoc.Vector{}
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s, text, _ := strings.Cut(text, " ")
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v.Offset = OFFSET[s]
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s, text, _ = strings.Cut(text, " ")
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v.Scale = aoc.Atoi(s)
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_, text, _ = strings.Cut(text, "(#")
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s, _, _ = strings.Cut(text, ")")
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return v, s
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}
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func fromColor(c string) aoc.Vector {
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scale, _ := strconv.ParseInt(c[:5], 16, 64)
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offset := OFFSET_INDEXES[c[5]-'0']
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return aoc.Vector{
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Offset: offset,
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Scale: int(scale),
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}
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}
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func findArea(vecs []aoc.Vector) int {
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shoelace := []aoc.Point{{0,0}}
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borderLength := 0
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for _, vec := range vecs {
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shoelace = append(shoelace, shoelace[len(shoelace)-1].Add(vec.Point()))
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borderLength += vec.Scale
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}
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return aoc.NumPoints(shoelace, borderLength)
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}
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