Zig-zag matrix
func zig_zag(w, h) {
var r = []
var n = 0
h.of { |e|
w.of { |f|
[e, f]
}
}.reduce('+').sort { |a, b|
(a[0]+a[1] <=> b[0]+b[1]) ||
(a[0]+a[1] -> is_even ? a[0]<=>b[0]
: a[1]<=>b[1])
}.each { |a|
r[a[1]][a[0]] = n++
}
return r
}
zig_zag(5, 5).each { say .join('', {|i| "%4i" % i}) }
Output:
0 1 5 6 14
2 4 7 13 15
3 8 12 16 21
9 11 17 20 22
10 18 19 23 24