My code works for the first one, but the second test in the attempt is:
Test Failed
Assert.That(actual, Is.EqualTo(expected))
Expected string length 56 but was 90. Strings differ at index 0.
Expected: "17 21 5 10 4 23 8 4 3 21 22 24 15 12 2 6 13 1 19 7 18 25"
But was: "\u0004\u001c!417 \u0013\u0005\021 5 <\u00136410 4 23 8 \r/:4 3 21 \u001e]:\u000522 24 \v*(_\f\u001b15 12 ..."
-----------^

I don't think it is my codes fault.
(Please don't give me a trouble shoot guide and marked as solved. It is useless.)