min_abs_diff_in_array.rb

n = gets.strip.to_i
a = gets.strip
arr = a.split(' ').map(&:to_i)
# your code goes here
min = 2147483647
arr.sort!
(1...arr.size).each do |i|
    diff = (arr[i - 1] - arr[i]).abs
    if diff < min
      min = diff
    end
end
puts min