aoc2024/day-16/internal/one/neighbours.go

package one

func neighbours(p node) [3]node {
	switch p.direction {
	case N:
		return [3]node{
			newNode(p.x, p.y-1, N),
			newNode(p.x-1, p.y, W),
			newNode(p.x+1, p.y, E),
		}
	case E:
		return [3]node{
			newNode(p.x+1, p.y, E),
			newNode(p.x, p.y-1, N),
			newNode(p.x, p.y+1, S),
		}
	case S:
		return [3]node{
			newNode(p.x, p.y+1, S),
			newNode(p.x-1, p.y, W),
			newNode(p.x+1, p.y, E),
		}
	case W:
		return [3]node{
			newNode(p.x-1, p.y, W),
			newNode(p.x, p.y+1, S),
			newNode(p.x, p.y-1, N),
		}
	default:
		return [3]node{}
	}
}