Add vent mapping solution

five/seafloor.go

@@ -0,0 +1,81 @@
+package five
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+)
+
+type seafloor struct {
+	input   []string
+	ventMap map[int]map[int]int
+}
+
+func (s *seafloor) load(filename string) error {
+	file, err := os.Open(filename)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+	scanner := bufio.NewScanner(file)
+	for scanner.Scan() {
+		s.input = append(s.input, scanner.Text())
+	}
+	return nil
+}
+
+func (s *seafloor) mapVents(diagonal bool) (int, error) {
+	var startX, startY, endX, endY int
+	s.ventMap = map[int]map[int]int{}
+	for _, vent := range s.input {
+		if count, err := fmt.Sscanf(vent, "%d,%d -> %d,%d", &startX, &startY, &endX, &endY); err != nil || count != 4 {
+			return -1, fmt.Errorf("scanned %d values: %w", count, err)
+		}
+
+		deltaX := endX - startX
+		deltaY := endY - startY
+
+		if !diagonal {
+			if deltaX != 0 && deltaY != 0 {
+				continue
+			}
+		}
+
+		x := startX
+		y := startY
+		completed := false
+		for !completed {
+			if s.ventMap[x] == nil {
+				s.ventMap[x] = map[int]int{}
+			}
+			s.ventMap[x][y]++
+			if x == endX && y == endY {
+				completed = true
+			} else {
+				if deltaX > 0 {
+					x++
+				} else if deltaX < 0 {
+					x--
+				}
+
+				if deltaY > 0 {
+					y++
+				} else if deltaY < 0 {
+					y--
+				}
+			}
+		}
+	}
+
+	overlap := 0
+
+	for xKey := range s.ventMap {
+		for yKey := range s.ventMap[xKey] {
+			if s.ventMap[xKey][yKey] > 1 {
+				overlap++
+			}
+		}
+	}
+
+	return overlap, nil
+}