a = [2.0, 1.2, 8.5, 1.2]
b = [1, 2, 3, 4]
p c = a.zip(b).sort_by {|a, b| a } # => [[1.2, 4], [1.2, 2], [2.0, 1], [8.5, 3]]
p c.map(&:last) # => [4, 2, 1, 3]
CmEgPSBbMi4wLCAxLjIsIDguNSwgMS4yXQpiID0gWzEsIDIsIDMsIDRdCnAgYyA9IGEuemlwKGIpLnNvcnRfYnkge3xhLCBifCBhIH0gICMgPT4gW1sxLjIsIDRdLCBbMS4yLCAyXSwgWzIuMCwgMV0sIFs4LjUsIDNdXQpwIGMubWFwKCY6bGFzdCkgIyA9PiBbNCwgMiwgMSwgM10K
[[1.2, 4], [1.2, 2], [2.0, 1], [8.5, 3]]
[4, 2, 1, 3]