snail

snail.go

package main

import "fmt"

func main() {
	n := 0
	fmt.Scanf("%d\n", &n)

	arr := make([][]int, n)

	cur := 1
	topPad, leftPad, rightPad, botPad := 0, -1, n, n

	for i := 0; i < n; i++ {
		arr[i] = make([]int, n)
	}

	pos := uint8(0)
	x, y := 0, 0
	for {
		if n*n < cur {
			break
		}
		switch pos {
		case 0:
			for i := x; i < rightPad; i++ {
				arr[i][y] = cur
				cur++
				x = i
			}
			y++
			rightPad--
			pos = 1
		case 1:
			for i := y; i < botPad; i++ {
				arr[x][i] = cur
				cur++
				y = i
			}
			x--
			botPad--
			pos = 2
		case 2:
			for i := x; i > leftPad; i-- {
				arr[i][y] = cur
				cur++
				x = i
			}
			y--
			leftPad++
			pos = 3
		case 3:
			for i := y; i > topPad; i-- {
				arr[x][i] = cur
				cur++
				y = i
			}
			x++
			topPad++
			pos = 0
		}
	}
	for i := 0; i < n; i++ {
		for j := 0; j < n; j++ {
			fmt.Printf("%3d ", arr[j][i])
		}
		fmt.Println()
	}
}