88 lines
2.0 KiB
Go
88 lines
2.0 KiB
Go
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package main
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import ("os"; "strings"; "fmt"; "strconv"; "regexp")
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type Board struct {
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width uint8
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height uint8
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}
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type Robot struct {
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x uint8
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y uint8
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vx int8
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vy int8
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}
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func (r Robot) Step(b Board, n uint) Robot {
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pos_vx := int(r.vx)
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pos_vy := int(r.vy)
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if pos_vx < 0 { pos_vx = int(b.width) + pos_vx }
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if pos_vy < 0 { pos_vy = int(b.height) + pos_vy }
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new_x := uint( uint(r.x) + uint(pos_vx) * n ) % uint(b.width)
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new_y := uint( uint(r.y) + uint(pos_vy) * n ) % uint(b.height)
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return Robot{uint8(new_x), uint8(new_y), r.vx, r.vy}
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}
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func check(e error) {
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if e != nil {
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panic(e)
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}
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}
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func abs(n int) uint {
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if n < 0 { return uint(-n) }
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return uint(n)
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}
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func NewRobot(line string) Robot {
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pattern := regexp.MustCompile(`-?\d+`)
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matches := pattern.FindAllString(line, -1)
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numbers := [4]int{}
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for i, match := range matches {
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num, err := strconv.Atoi(match)
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check(err)
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numbers[i] = num
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}
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return Robot{uint8(numbers[0]), uint8(numbers[1]), int8(numbers[2]), int8(numbers[3])}
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}
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func main() {
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dat, err := os.ReadFile("data.txt")
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check(err)
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lines := strings.Split(strings.TrimSpace(string(dat)), "\n")
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board := Board{101, 103}
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robots := make([]Robot, 0, 100)
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for _, line := range lines {
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robots = append(robots, NewRobot(line))
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}
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// run simulation
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for i := range robots {
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robots[i] = robots[i].Step(board, 100)
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}
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// count in quadrants
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q1, q2, q3, q4 := 0, 0, 0, 0
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for _, r := range robots {
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switch {
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case r.x < (board.width / 2) && r.y < (board.height / 2): q1++
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case r.x > (board.width / 2) && r.y < (board.height / 2): q2++
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case r.x < (board.width / 2) && r.y > (board.height / 2): q3++
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case r.x > (board.width / 2) && r.y > (board.height / 2): q4++
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}
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}
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fmt.Println(q1, q2, q3, q4)
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fmt.Println(q1 * q2 * q3 * q4)
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}
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