99 lines
2.3 KiB
Go
99 lines
2.3 KiB
Go
package day9
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import (
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"bytes"
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"cmp"
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"fmt"
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"slices"
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"strconv"
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"git.bizdoc.ro/gabi-public/Advent-of-Code.git/aoc"
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"git.bizdoc.ro/private/devkit.git/collections/geometry/v2"
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)
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type Rectangle struct {
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Point1, Point2 int
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Top, Bottom geometry.Point
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Area float64
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}
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func (r Rectangle) String() string {
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v := r.Vertices()
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var b bytes.Buffer
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fmt.Fprintln(&b, r.Top, r.Bottom)
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for _, v := range v {
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fmt.Fprintf(&b, "[{x:%2d y:%2d} -> {x:%2d y:%2d}] ", v.Start.Line, v.Start.Col, v.End.Line, v.End.Col)
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}
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fmt.Fprintf(&b, " a = %f", r.Area)
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return b.String()
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}
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func (r Rectangle) Vertices() (v [4]Vertex) {
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v[0] = Vertex{
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Start: r.Top,
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End: geometry.NewPoint(r.Top.Line, r.Bottom.Col),
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Facing: geometry.DirectionRight,
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}
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v[1] = Vertex{
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Start: v[0].End,
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End: r.Bottom,
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Facing: geometry.DirectionDown,
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}
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v[2] = Vertex{
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Start: v[1].End,
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End: geometry.NewPoint(r.Bottom.Line, r.Top.Col),
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Facing: geometry.DirectionLeft,
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}
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v[3] = Vertex{
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Start: v[2].End,
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End: r.Top,
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Facing: geometry.DirectionUp,
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}
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return
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}
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func Part1(ctx aoc.Context) (int, error) {
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g, err := geometry.ScannerToGrid(ctx.Scanner(), ",", strconv.Atoi)
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if err != nil {
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return 0, fmt.Errorf("day9: failed to parse intput %w", err)
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}
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points := geometry.UnsafeGridData(g)
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for _, point := range points {
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point[1], point[0] = point[0], point[1]
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}
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return int(day9FindRectangles(points)[0].Area), nil
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}
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func day9FindRectangles(points [][]int) []Rectangle {
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const lineIndex = 0
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const colIndex = 1
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var pairs []Rectangle
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var abs = func(a int) int {
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if a < 0 {
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a = -a
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}
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return a
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}
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for i, p1 := range points {
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for j, p2 := range points[i+1:] {
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x := abs(p1[colIndex]-p2[colIndex]) + 1
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y := abs(p1[lineIndex]-p2[lineIndex]) + 1
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d := float64(x) * float64(y)
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//fmt.Printf("%d,%d - %d,%d (%d-%d)%g\n", p1[colIndex], p1[lineIndex], p2[colIndex], p2[lineIndex], x, y, d)
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pairs = append(pairs, Rectangle{
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Point1: i,
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Point2: i + 1 + j,
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Top: geometry.NewPoint(min(p1[lineIndex], p2[lineIndex]), min(p1[colIndex], p2[colIndex])),
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Bottom: geometry.NewPoint(max(p1[lineIndex], p2[lineIndex]), max(p1[colIndex], p2[colIndex])),
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Area: d,
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})
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}
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}
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slices.SortFunc(pairs, func(a, b Rectangle) int {
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return cmp.Compare(b.Area, a.Area) // reverse order
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})
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return pairs
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}
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