feat: solve PartOne using DFS algorithm

internal/2025/DaySeven/code.go

@@ -0,0 +1,73 @@
+package dayseven
+
+import (
+	"advent-of-code/internal/registry"
+	"os"
+	"strings"
+)
+
+func init() {
+	registry.Register("2025D7", ParseInput, PartOne, PartTwo)
+}
+
+type Position struct {
+	row    int
+	column int
+}
+
+func ParseInput(filepath string) []string {
+	content, _ := os.ReadFile(filepath)
+	return strings.Split(string(content), "\n")
+}
+
+func findStart(input []string) (int, int) {
+	for row := range input {
+		if column := strings.IndexByte(input[row], 'S'); column != -1 {
+			return row, column
+		}
+	}
+	return -1, -1
+}
+
+func PartOne(input []string) int {
+	rows, columns := len(input), len(input[0])
+
+	startRow, startColumn := findStart(input)
+
+	queue := []Position{{startRow, startColumn}}
+	activated := make(map[Position]bool)
+	splits := 0
+
+	for len(queue) > 0 {
+		current := queue[0]
+		queue = queue[1:]
+
+		row := current.row + 1
+		column := current.column
+
+		for row < rows && input[row][column] != '^' {
+			row++
+		}
+
+		if row < rows {
+			splitPosition := Position{row, column}
+			if !activated[splitPosition] {
+				activated[splitPosition] = true
+				splits++
+
+				if column > 0 {
+					queue = append(queue, Position{row, column - 1})
+				}
+				if column < columns-1 {
+					queue = append(queue, Position{row, column + 1})
+				}
+			}
+		}
+	}
+
+	return splits
+}
+
+func PartTwo(data []string) int {
+	return 0
+}