Selection sort

def insert(a, index, value)
  i = index
  while(index >= 0 && value < a[i])
    a[i+1] = a[i]
    i -= 1
  end
  a[i+1] = value
end

def selection_sort(a)
  (1).upto(a.length-1) do |i|
    insert(a, i-1, a[i])
  end
  a
end