This is the problem I'm stuck on, I don't think this is actually completeable. using my IDE I coded up this:
List al1= Arrays.asList();
List al2= Arrays.asList();
pln(""+al1+al2); //[][]
pln(""+(al1==al2)); //false
pln((Arrays.asList()==Arrays.asList())+""); //false
Java will always compare the references here and not the content so idk how people passed this in java

All test ran successfully except three which is returning [
// assertEquals(Arrays.asList(), RepeatingWord.findWord(" ... "));
// assertEquals(Arrays.asList(), RepeatingWord.findWord(" ' "));
// assertEquals(Arrays.asList(), RepeatingWord.findWord(" ''' "));

Getting error of comparison of
org.opentest4j.AssertionFailedError: expected: java.util.Arrays$ArrayList@5abca1e0<[]> but was: java.util.ArrayList@2286778<[]>
how ever i am using comparator and in comparison its giving error in unit test only.

yes actually, missed one test case. thanks

@qy201706 Instead of changing the function parameter,
construct a std::string from the input in within your function.

For instance, use:

string in_string(in);

should give an in_string string object which you can use to examine for duplicates.

the test is the alphabet in lowercase and uppercase... there are 26 letters in the alphabet

abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZReturnsTwentySix

How its expecting 26? It should be 13