day 15a complete

used help to get solution (see graph library used)

day15/15a/main.go

@@ -0,0 +1,108 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"strconv"
+
+	"github.com/yourbasic/graph"
+)
+
+func main() {
+	content := returnContent("../input")
+	//content := returnContent("../testInput")
+
+	height := len(*content)
+	width := len((*content)[0])
+
+	g := graph.New(height * width)
+
+	for y, line := range *content {
+		for x, _ := range line {
+			c := Coordinate{
+				X: x,
+				Y: y,
+			}
+			myIdx := c.Y*width + c.X
+			neighbours := c.Neighbours(width, height, false)
+			for _, neighbour := range neighbours {
+				neighbourCost := int64((*content)[neighbour.Y][neighbour.X])
+				neighbourIdx := neighbour.Y*width + neighbour.X
+				g.AddCost(myIdx, neighbourIdx, neighbourCost)
+			}
+		}
+	}
+
+	path, cost := graph.ShortestPath(g, 0, width*height-1)
+
+	fmt.Println(path, cost)
+}
+
+type Coordinate struct {
+	X int
+	Y int
+}
+
+func (c *Coordinate) Neighbours(gridWidth int, gridHeight int, diagonal bool) (out []Coordinate) {
+	spaceLeft := c.X > 0
+	spaceRight := c.X < gridWidth-1
+	spaceUp := c.Y > 0
+	spaceDown := c.Y < gridHeight-1
+
+	if spaceLeft {
+		out = append(out, Coordinate{c.X - 1, c.Y})
+	}
+	if spaceRight {
+		out = append(out, Coordinate{c.X + 1, c.Y})
+	}
+	if spaceUp {
+		out = append(out, Coordinate{c.X, c.Y - 1})
+	}
+	if spaceDown {
+		out = append(out, Coordinate{c.X, c.Y + 1})
+	}
+
+	if diagonal {
+		if spaceUp && spaceLeft {
+			out = append(out, Coordinate{c.X - 1, c.Y - 1})
+		}
+		if spaceUp && spaceRight {
+			out = append(out, Coordinate{c.X + 1, c.Y - 1})
+		}
+		if spaceDown && spaceLeft {
+			out = append(out, Coordinate{c.X - 1, c.Y + 1})
+		}
+		if spaceDown && spaceRight {
+			out = append(out, Coordinate{c.X + 1, c.Y + 1})
+		}
+	}
+
+	return
+}
+
+func returnContent(path string) *[][]int {
+	//read file and return it as an array of integers
+
+	file, err := os.Open(path)
+	var content [][]int
+
+	if err != nil {
+		fmt.Println("Unlucky, the file didn't open")
+		return &content
+	}
+	defer file.Close()
+
+	scanner := bufio.NewScanner(file)
+
+	for scanner.Scan() {
+		nums := []int{}
+		for _, num := range scanner.Text() {
+			val, _ := strconv.Atoi(string(num))
+			nums = append(nums, val)
+		}
+		content = append(content, nums)
+	}
+
+	return &content
+}