day4

2024/go/day04/day04.go

@@ -0,0 +1,59 @@
+package day04
+
+import (
+	"adventofcode2024/utils/grid2d"
+	"adventofcode2024/utils/inputs"
+)
+
+func Part1(input string) int {
+	val := 0
+	grid := inputs.ToGrid2D(input, "\n", "", '.', func(c string) rune { return rune(c[0])})
+	directions := [][]int{{0,1},{0,-1},{1,0},{-1,0},{-1,1},{1,1},{-1,-1},{1,-1}}
+	for j := 0; j < grid.SizeY(); j++ {
+		for i := 0; i < grid.SizeX(); i++ {
+			if  !checkChar(i, j, grid, 'X') { continue }			
+			for _, dir := range directions {
+				x := i + dir[0]
+				y := j + dir[1]
+				if !checkChar(x, y, grid, 'M') { continue }
+				x = x + dir[0]
+				y = y + dir[1]				
+				if !checkChar(x, y, grid, 'A') { continue }
+				x = x + dir[0]
+				y = y + dir[1]				
+				if !checkChar(x, y, grid, 'S') { continue }
+				val++
+			}
+		}
+	}
+	return val
+}
+
+func Part2(input string) int {
+	val := 0
+	grid := inputs.ToGrid2D(input, "\n", "", '.', func(c string) rune { return rune(c[0])})
+	dir1 := [][]int{{-1,1},{1,-1},}
+	dir2 := [][]int{{1,1},{-1,-1}}
+	for j := 0; j < grid.SizeY(); j++ {
+		for i := 0; i < grid.SizeX(); i++ {
+			if !checkChar(i, j, grid, 'A') { continue }
+			if 
+			(checkChar(i + dir1[0][0], j + dir1[0][1], grid, 'M') && checkChar(i + dir1[1][0], j +  dir1[1][1], grid, 'S') ||
+			checkChar(i + dir1[0][0], j +  dir1[0][1], grid, 'S') && checkChar(i + dir1[1][0], j +  dir1[1][1], grid, 'M')) &&
+			(checkChar(i + dir2[0][0], j + dir2[0][1], grid, 'M') && checkChar(i + dir2[1][0], j +  dir2[1][1], grid, 'S') ||
+			checkChar(i + dir2[0][0], j +  dir2[0][1], grid, 'S') && checkChar(i + dir2[1][0], j +  dir2[1][1], grid, 'M') ) {
+				val++ 
+			}
+		}
+	}
+	return val}
+
+func checkChar(x int, y int, grid *grid2d.Grid[rune], c rune) bool {
+	if x < 0 || x >= grid.SizeX() || y < 0 || y >= grid.SizeY() {
+		return false
+	}
+	if grid.Get(x, y) == c {
+		return true
+	}
+	return false
+}