adventofcode

commit: 52287f3419080ae4230f97d71075896623e5a242
parent: 519e35d37da4221abe56a4ea21775cc29c5fbf39
Author: Haelwenn (lanodan) Monnier <contact@hacktivis.me>
Date:   Tue,  3 Dec 2019 12:38:00 +0100

day2: fix position registration

forgetting the difference between point and line isn’t a good idea

Diffstat:
M
day2.go
56
++++++++++++++++++++++++++------------------------------

1 file changed, 26 insertions(+), 30 deletions(-)
diff --git a/day2.go b/day2.go
@@ -6,32 +6,33 @@ import (
 	"strings"
 )
 
-func line_positions(line string) [][2]int {
+func line_positions(line string) (positions [][2]int) {
 	line_split := strings.Split(line, ",")
 	fmt.Printf("%9s\n", line_split)
 	position := [2]int{0, 0} // (x,y)
-	positions := make([][2]int, len(line_split))
 
-	for i, move := range line_split {
+	for _, move := range line_split {
 		direction := strings.Split(move, "")[0]
 		amount, err := strconv.Atoi(move[1:])
 		if err != nil {
 			fmt.Printf("Error: %s", err)
 		}
 
-		switch direction {
-		case "U":
-			position[0] += amount
-		case "D":
-			position[0] -= amount
-		case "L":
-			position[1] += amount
-		case "R":
-			position[1] -= amount
+		for i := 0; i < amount; i++ {
+			switch direction {
+			case "U":
+				position[0]++
+			case "D":
+				position[0]--
+			case "L":
+				position[1]++
+			case "R":
+				position[1]--
+			}
+
+			positions = append(positions, position)
 		}
 
-		positions[i] = position
-
 		// fmt.Printf("%s%02d(% 4d,% 4d)\n", direction, amount, position[0], position[1])
 	}
 
@@ -40,26 +41,21 @@ func line_positions(line string) [][2]int {
 	return positions
 }
 
-func Intersection(a, b [][2]int) (c [][2]int) {
-	m := make(map[[2]int]bool)
-
-	for _, item := range a {
-		m[item] = true
-	}
-
-	for _, item := range b {
-		if _, ok := m[item]; ok {
-			c = append(c, item)
-		}
-	}
-	return
-}
-
 func main() {
 	//line1 := line_positions("R75,D30,R83,U83,L12,D49,R71,U7,L72")
 	//line2 := line_positions("U62,R66,U55,R34,D71,R55,D58,R83")
 	line1 := line_positions("R98,U47,R26,D63,R33,U87,L62,D20,R33,U53,R51")
 	line2 := line_positions("U98,R91,D20,R16,D67,R40,U7,R15,U6,R7")
 
-	fmt.Printf("%3d\n", Intersection(line1, line2))
+	var intercepts [][2]int
+
+	for _, pos1 := range line1 {
+		for _, pos2 := range line2 {
+			if pos1 == pos2 {
+				intercepts = append(intercepts, pos1)
+			}
+		}
+	}
+
+	fmt.Printf("%3d\n", intercepts)
 }