#!/usr/bin/ruby
#
## https://rosettacode.org/wiki/Equilibrium_index
#
func eq_index(nums) {
    var (i, sum, sums) = (0, 0, Hash.new)
    nums.each { |n|
        sums{2*sum + n} := [] -> append(i++)
        sum += n;
    }
    sums{sum} \\ [];
};
var indices = [
  [-7, 1, 5, 2,-4, 3, 0],
  [2, 4, 6],
  [2, 9, 2],
  [1,-1, 1,-1, 1,-1, 1],
];
indices.each { |x|
    say ("%s => %s" % [x, eq_index(x)].map{.dump}...);
};