2024.08 WIP

Author: jerodev

2024/8-antenna/example.txt

@@ -0,0 +1,12 @@
+............
+........0...
+.....0......
+.......0....
+....0.......
+......A.....
+............
+............
+........A...
+.........A..
+............
+............

2024/8-antenna/input.txt

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+.............C.7..................G..0...y........
+..................7................C..............
+....................................0......W....y.
+.......................................D..W.......
+..........u.......................................
+..................................4.......D0...j..
+.....................................D............
+................O.....C................G..........
+............F.....................C...............
+......u..........F.................4.......y......
+..........X..........5....4...........1...........
+..........F...........5X...................3......
+.............F.............................j.3....
+.................u..............X.................
+............................7.....................
+..................................................
+..........................5.....j2.........4......
+....d.....................y...................j1..
+..................................................
+............................Y.e...................
+.................d...X...............J...........e
+.............d....................................
+..............................Y..............1....
+.........................................Y........
+......................W......8..f...J.........3...
+.......w.............J............................
+...................................U.....f......e.
+.................................Of....e....t...1.
+.......g..........d......s........................
+................G................f................
+.....................................O............
+...g........................T.....U...............
+......................s..........T.............G..
+................................s.......8.........
+.....9........g...........o...U............E......
+............g............................t....o...
+...........................................6....E.
+.....................s......x........6....E.......
+..........w.9................x............t.......
+...........9........w...........J.....6o..........
+.............................................o....
+..........S................U......................
+.......S..2..........c........T.O....t............
+.....2...S.....c...................T..............
+..................x.......................8.......
+....9.............................................
+...wS.....................................6.......
+................2........................8........
+..................................................
+.................x....c........................E..

2024/8-antenna/main.go

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+package main
+
+import (
+	"advent-of-code/util"
+	"bufio"
+	"fmt"
+	"math"
+	"slices"
+)
+
+const nothing = '.'
+
+func main() {
+	file := util.FileFromArgs()
+	scan := bufio.NewScanner(file)
+
+	antennas := map[byte][]position{}
+
+	var grid [][]byte
+	var row []byte
+	for scan.Scan() {
+		row = scan.Bytes()
+		for i := range row {
+			if row[i] != nothing {
+				if _, ok := antennas[row[i]]; !ok {
+					antennas[row[i]] = []position{}
+				}
+
+				antennas[row[i]] = append(antennas[row[i]], position{i, len(grid)})
+			}
+		}
+
+		grid = append(grid, row)
+	}
+
+	var antinodes, points []position
+	for k := range antennas {
+		for i := range antennas[k] {
+			for j := range antennas[k] {
+				if i == j {
+					continue
+				}
+
+				points = calculateAntinodes(antennas[k][i], antennas[k][j])
+				for p := range points {
+					if slices.IndexFunc(antinodes, func(pp position) bool { return points[p].eq(pp) }) == -1 {
+						antinodes = append(antinodes, points[p])
+					}
+				}
+
+			}
+		}
+	}
+
+	fmt.Println(len(antinodes))
+}
+
+type position struct {
+	X, Y int
+}
+
+func (p position) eq(q position) bool {
+	return p.X == q.X && p.Y == q.Y
+}
+
+// calculateAntinodes will calculate all antinodes between two antennas
+func calculateAntinodes(c1, c2 position) []position {
+	var positions []position
+
+	// sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2));
+	d := math.Sqrt(float64((c1.X-c2.X)*(c1.X-c2.X) + (c1.Y-c2.Y)*(c1.Y-c2.Y)))
+
+	for r := range 20 {
+		if d > float64(r+2*r) {
+			continue // Circles don't touch
+		}
+
+		// TODO: calculate touch points
+	}
+
+	return positions
+}