hackathon/question/q01.go

package question

import (
	_ "embed"
	"fmt"
	"math"
	"math/rand"
	"strconv"
	"strings"

	"github.com/hhhapz/codequest/models"
)

func move(x, y int, dir byte, step int) (int, int) {
	switch dir {
	case 'N':
		return x, y + step
	case 'S':
		return x, y - step
	case 'E':
		return x + step, y
	case 'W':
		return x - step, y
	}
	return x, y
}

func q1P1(steps []string) (x int, y int) {
	for _, step := range steps {
		dir := step[0]
		amt, _ := strconv.Atoi(step[1:])
		x, y = move(x, y, dir, amt)
	}
	return
}

func q1P2(steps []string) (x int, y int) {
	known := make(map[int]map[int]bool)

	for _, step := range steps {
		dir := step[0]
		amt, _ := strconv.Atoi(step[1:])
		x, y = move(x, y, dir, amt)

		if known[x] == nil {
			known[x] = make(map[int]bool)
		}
		if known[x][y] {
			return
		}
		known[x][y] = true
	}
	return
}

func q1Total(a, b int) int {
	if a < 0 {
		a = -a
	}
	if b < 0 {
		b = -b
	}
	return a + b
}

const (
	q1Entries  = 100
	q1Range    = 20
	directions = "NSWE"
)

func init() {
	var q *Question
	q = &Question{
		ID:    "directions",
		Text:  q01Text,
		Level: Level1,
		Generate: func(u *models.User) string {
			res := make([]string, 0, 100)

			r := userRandom(u)

			known := make(map[int]map[int]bool)
			var x, y int
			for i := 0; i < q1Entries; i++ {
				dir := directions[r.Intn(4)]
				steps := r.Intn(30) + 1
				newX, newY := move(x, y, dir, steps)

				if known[newX] == nil {
					known[newX] = make(map[int]bool)
				}
				if known[newX][newY] {
					i--
					continue
				}

				known[newX][newY] = true
				x, y = newX, newY

				res = append(res, fmt.Sprintf("%c%d", dir, steps))
			}

			n := rand.Intn(q1Range) + 10
			locX, locY := q1P1(res[:n])

			n = rand.Intn(q1Range) + 35
			lastX, lastY := q1P1(res[:n])

			dX := math.Max(float64(locX), float64(lastX)) - math.Min(float64(locX), float64(lastX))
			dY := math.Max(float64(locY), float64(lastY)) - math.Min(float64(locY), float64(lastY))

			if locX > lastX {
				res[n] = fmt.Sprintf("E%d", int(dX))
				n++
			} else if locX < lastX {
				res[n] = fmt.Sprintf("W%d", int(dX))
				n++
			}

			if locY > lastY {
				res[n] = fmt.Sprintf("N%d", int(dY))
			} else if locY < lastY {
				res[n] = fmt.Sprintf("S%d", int(dY))
			}

			return strings.Join(res, "\n")
		},

		Validate: func(u *models.User, level Part, input string) bool {
			raw := q.Generate(u)
			inp := strings.Split(raw, "\n")

			switch level {
			case Part1:
				x, y := q1P1(inp)
				return q1Total(x, y) == 0
			case Part2:
				x, y := q1P2(inp)
				return q1Total(x, y) == 0
			}
			return false
		},
	}

	Register(q)
}

//go:embed prompts/q01.md
var q01Text string