days

2024/go/day08/day08.go

@@ -0,0 +1,168 @@
+package day08
+
+import (
+	"adventofcode2024/utils/grid2d"
+	"adventofcode2024/utils/inputs"
+	"fmt"
+)
+
+type loc struct {
+	x int
+	y int
+}
+
+type pt struct {
+	display   rune
+	antinodes int
+	paired    map[loc]pt
+	visited   map[rune]bool
+}
+
+func Part1(input string) int {
+	grid := inputs.ToGrid2D(input, "\n", "", pt{display: '.'}, func(c string) pt { return pt{display: rune(c[0]), paired: make(map[loc]pt), visited: make(map[rune]bool)} })
+	for x1 := 0; x1 < grid.SizeX(); x1++ {
+		for y1 := 0; y1 < grid.SizeY(); y1++ {
+			pt1 := grid.Get(x1, y1)
+			if pt1.display != '.' {
+				for x2 := 0; x2 < grid.SizeX(); x2++ {
+					for y2 := 0; y2 < grid.SizeY(); y2++ {
+						pt2 := grid.Get(x2, y2)
+						if x1 != x2 && y1 != y2 && pt1.display == pt2.display && !isPaired(x1, y1, pt1, pt2) {
+							pt1.paired[loc{x: x2, y: y2}] = pt2
+							pt2.paired[loc{x: x1, y: y1}] = pt1
+						}
+					}
+				}
+			}
+		}
+	}
+	for x := 0; x < grid.SizeX(); x++ {
+		for y := 0; y < grid.SizeY(); y++ {
+			pt1 := grid.Get(x, y)
+			if pt1.display != '.' {
+				for ploc := range pt1.paired {
+					addAntiNodes(x, y, ploc.x, ploc.y, grid)
+				}
+			}
+		}
+	}
+	antinodes := 0
+	for x := 0; x < grid.SizeX(); x++ {
+		for y := 0; y < grid.SizeY(); y++ {
+			pt := grid.Get(x, y)
+			if pt.antinodes > 0 {
+				antinodes++
+			}
+		}
+	}
+	return antinodes
+}
+
+func Part2(input string) int {
+	grid := inputs.ToGrid2D(input, "\n", "", pt{display: '.'}, func(c string) pt { return pt{display: rune(c[0]), paired: make(map[loc]pt), visited: make(map[rune]bool)}})
+	for x1 := 0; x1 < grid.SizeX(); x1++ {
+		for y1 := 0; y1 < grid.SizeY(); y1++ {
+			pt1 := grid.Get(x1, y1)
+			if pt1.display != '.' {
+				for x2 := 0; x2 < grid.SizeX(); x2++ {
+					for y2 := 0; y2 < grid.SizeY(); y2++ {
+						pt2 := grid.Get(x2, y2)
+						if x1 != x2 && y1 != y2 && pt1.display == pt2.display && !isPaired(x1, y1, pt1, pt2) {
+							pt1.paired[loc{x: x2, y: y2}] = pt2
+							pt2.paired[loc{x: x1, y: y1}] = pt1
+							pt1.antinodes++
+							pt2.antinodes++
+							grid.Set(x1, y1, pt1)
+							grid.Set(x2, y2, pt2)
+						}
+					}
+				}
+			}
+		}
+	}
+	for x := 0; x < grid.SizeX(); x++ {
+		for y := 0; y < grid.SizeY(); y++ {
+			pt1 := grid.Get(x, y)
+			if pt1.display != '.' {
+				for ploc := range pt1.paired {
+					addAntiNodes_p2(pt1.display, x, y, ploc.x, ploc.y, grid)
+				}
+			}
+		}
+	}
+	antinodes := 0
+	fmt.Printf("%v\n", grid.StringWithFormatter(formatter))
+	for x := 0; x < grid.SizeX(); x++ {
+		for y := 0; y < grid.SizeY(); y++ {
+			pt := grid.Get(x, y)
+			if pt.antinodes > 0 {
+				antinodes++
+			} else {
+				if pt.display != '.' { antinodes++ }
+			}
+		}
+	}
+	return antinodes
+}
+
+func formatter(p pt, x int, y int) string {
+	if p.antinodes > 0 { 
+		return "#"
+	}
+	return "."
+}
+
+func isPaired(x int, y int, p1 pt, pt2 pt) bool {
+	return p1.paired[loc{x: x, y: y}].display == pt2.display
+}
+
+func addAntiNodes(x1 int, y1 int, x2 int, y2 int, grid *grid2d.Grid[pt]) {
+	px1, py1, px2, py2 := offsetPoints(x1, y1, x2, y2)
+
+	if px1 < 0 || px1 >= grid.SizeX() || py1 < 0 || py1 >= grid.SizeY() {
+		return
+	}
+	pt1 := grid.Get(px1, py1)
+	pt1.antinodes++
+	grid.Set(px1, py1, pt1)
+	if px2 < 0 || px2 >= grid.SizeX() || py2 < 0 || py2 >= grid.SizeY() {
+		return
+	}
+	pt2 := grid.Get(px2, py2)
+	pt2.antinodes++
+	grid.Set(px2, py2, pt2)
+}
+
+func addAntiNodes_p2(frequency rune, x1 int, y1 int, x2 int, y2 int, grid *grid2d.Grid[pt]) {
+	px1, py1, px2, py2 := offsetPoints(x1, y1, x2, y2)
+	if !(px1 < 0 || px1 >= grid.SizeX() || py1 < 0 || py1 >= grid.SizeY()) {
+		pt1 := grid.Get(px1, py1)
+		if !pt1.visited[frequency] {
+			pt1.antinodes++
+			pt1.visited[frequency] = true
+			grid.Set(px1, py1, pt1)
+			addAntiNodes_p2(frequency, x1, y1, px1, py1, grid)
+		}
+	}
+	if !(px2 < 0 || px2 >= grid.SizeX() || py2 < 0 || py2 >= grid.SizeY()) {
+		pt2 := grid.Get(px2, py2)
+		if !pt2.visited[frequency] {
+			pt2.antinodes++
+			pt2.visited[frequency] = true
+			grid.Set(px2, py2, pt2)
+			addAntiNodes_p2(frequency, x2, y2, px2, py2, grid)
+		}
+	}
+}
+
+// Function to calculate two points symmetrically placed above and below the line
+func offsetPoints(x1, y1, x2, y2 int) (int, int, int, int) {
+	dx := x1 - x2
+	dy := y1 - y2
+
+	p1x := x1 + dx
+	p1y := y1 + dy
+	p2x := x2 - dx
+	p2y := y2 - dy
+	return p1x, p1y, p2x, p2y
+}