# Write a method that takes in a string and an array of indices in the
# string. Produce a new string, which contains letters from the input
# string in the order specified by the indices of the array of indices.
#
# Difficulty: medium.

def scramble_string(string, positions)
  i=0
  result=""

  while i<string.length
    result+=string[positions[i]]
    i+=1
  end

  return result
end

# These are tests to check that your code is working. After writing
# your solution, they should all print true.

puts("\nTests for #scramble_string")
puts("===============================================")
    puts(
      'scramble_string("abcd", [3, 1, 2, 0]) == "dbca": ' +
      (scramble_string("abcd", [3, 1, 2, 0]) == "dbca").to_s
    )
    puts(
      'scramble_string("markov", [5, 3, 1, 4, 2, 0]) == "vkaorm"): ' +
      (scramble_string("markov", [5, 3, 1, 4, 2, 0]) == "vkaorm").to_s
    )
puts("===============================================")