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https://github.com/onyx-and-iris/aoc2023.git
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37 lines
924 B
Go
37 lines
924 B
Go
package main
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import (
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"math"
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"strings"
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)
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func fromHex(imager *imager, lines []string) {
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for _, line := range lines {
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direction, count := func() (string, int) {
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var dirs = []string{"R", "D", "L", "U"}
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m := getParams(r, line)
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code := strings.TrimLeft(m["colour"], "#")
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return dirs[mustConv(string(code[len(code)-1]))], mustConvHex(code[:len(code)-1])
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}()
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imager.add(direction, count)
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}
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}
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// two returns the area of the polygon described by imager.space
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// it uses the hex codes to define points
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func two(lines []string) int {
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imager := newImager()
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buildImage(fromHex, imager, lines)
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area := 0
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for i := 0; i < len(imager.space); i++ {
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next := imager.space[(i+1)%len(imager.space)]
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area += imager.space[i].X*next.Y - imager.space[i].Y*next.X
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}
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// add perimeter to area within perimeter
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area = len(imager.space) + (int(math.Abs(float64(area))) / 2)
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return area - len(imager.space)/2 + 1
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}
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