Partial solution for 10.1. We've got grouping, but still need sorting and some printing cleanup.

2018/internal/day10/point.go

@@ -0,0 +1,77 @@
+package day10
+
+import (
+	"fmt"
+)
+
+type Point struct {
+	X, Y   int
+	Xv, Yv int
+}
+
+func (p *Point) Move() {
+	p.X += p.Xv
+	p.Y += p.Yv
+}
+
+func DrawPoints(points []*Point) {
+	pointArr := makeBuffer(points)
+
+	// print the buffer
+	for y := 0; y < len(pointArr[0]); y++ {
+		for x := 0; x < len(pointArr); x++ {
+			if pointArr[x][y] != 0 {
+				fmt.Printf("%c", pointArr[x][y])
+			} else {
+				fmt.Printf(".")
+			}
+		}
+		fmt.Println()
+	}
+}
+
+// findBounds returns xMin, xMax, yMin, and yMax from the provided points.
+func findBounds(points []*Point) (int, int, int, int) {
+	// find min and max values
+	var xMin, xMax, yMin, yMax int
+	for _, point := range points {
+		if point.X < xMin {
+			xMin = point.X
+		}
+		if point.X > xMax {
+			xMax = point.X
+		}
+		if point.Y < yMin {
+			yMin = point.Y
+		}
+		if point.Y > yMax {
+			yMax = point.Y
+		}
+	}
+
+	return xMin, xMax, yMin, yMax
+}
+
+func makeBuffer(points []*Point) [][]byte {
+	xMin, xMax, yMin, yMax := findBounds(points)
+	// get the total magnitude; we'll do adjustments later
+	xRange := xMax - xMin
+	yRange := yMax - yMin
+
+	// construct the buffer
+	pointArr := make([][]byte, xRange+1)
+	for i := 0; i < len(pointArr); i++ {
+		pointArr[i] = make([]byte, yRange+1)
+	}
+
+	// put the points into the buffer
+	for _, p := range points {
+		// the x and y values are adjusted by the mins
+		x := p.X - xMin
+		y := p.Y - yMin
+
+		pointArr[x][y] = '#'
+	}
+
+	return pointArr
+}