95 lines
1.1 KiB
Go
95 lines
1.1 KiB
Go
package main
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import (
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"fmt"
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"os"
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"strconv"
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)
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const (
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// directions
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W = iota
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N
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E
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S
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)
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var (
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// current value
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cur int
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// current position
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x, y int
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// current direction
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dir int
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// grid bounds
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xmax, xmin, ymax, ymin int
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)
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func main() {
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n, err := strconv.Atoi(os.Args[1])
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if err != nil {
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os.Exit(1)
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}
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// move current position in grid and compute change direction, expand grid
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for cur < n {
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nextMove()
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// fmt.Println(cur, x, y)
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}
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// distance to position
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fmt.Println(Abs(x) + Abs(y))
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}
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func nextMove() {
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if cur == 0 {
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dir = S
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} else {
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x1, y1 := dirMove()
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if outOfBound(x1, y1) {
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changeDir()
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x1, y1 = dirMove()
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}
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x, y = x1, y1
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}
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cur++
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}
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func dirMove() (int, int) {
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switch dir {
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case W:
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return x - 1, y
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case N:
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return x, y + 1
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case E:
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return x + 1, y
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case S:
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return x, y - 1
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default:
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return x, y
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}
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}
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func outOfBound(x1 int, y1 int) bool {
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return x1 > xmax || x1 < xmin || y1 > ymax || y1 < ymin
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}
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func changeDir() {
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switch dir {
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case W:
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dir = S
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ymin--
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case N:
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dir = W
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xmin--
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case E:
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dir = N
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ymax++
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case S:
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dir = E
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xmax++
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}
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}
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func Abs(n int) int {
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if n < 0 {
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return -n
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}
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return n
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}
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