Write a program that will display a spiral of n × n numbers. Make sure your program uses constant (or linear) space. This means, it is not allowed to build an array before printing it (or to build another data structure consuming space with O(pow n).

Sperate numbers with one space.

Example

For example, here’s what the spiral looks like for n = 10:

99 98 97 96 95 94 93 92 91 90
64 63 62 61 60 59 58 57 56 89
65 36 35 34 33 32 31 30 55 88
66 37 16 15 14 13 12 29 54 87
67 38 17  4  3  2 11 28 53 86
68 39 18  5  0  1 10 27 52 85
69 40 19  6  7  8  9 26 51 84
70 41 20 21 22 23 24 25 50 83
71 42 43 44 45 46 47 48 49 82
72 73 74 75 76 77 78 79 80 81

Run it

As this function doesn’t have return value, but yields an output, use go run to test output:

go run spiral.go