g964 // I solved this problem. It was my mistake. I should've considered "No input" case.

std::string s = "who hit retaining The That a we taken"; // Passed
std::string sol = "who RETAINING hit THAT a THE we TAKEN";
dotest(s, sol);
s = "on I came up were so grandmothers"; //Non-Passed
sol = "i CAME on WERE up GRANDMOTHERS so";
dotest(s, sol);

Thanks for your reply
I tried

the first line : cout<<"Input : "<<strng<<endl;
the last line : cout<<"Result :" <<result<<endl;

And all I can see in the log is

Input : who hit retating... (which is right input value)
Result : who RETATING hit... (which is also right answer)
Input : (No input value?)
"Caught unknown exception"

So I mean taka seems having trouble bringing Input value after the first fixed test.

(In the Sample test)

Fixed test : Pass

(but in the final test)

Fixed test : Non-pass
Random test : Pass

what is possibly wrong with my code? I thought the fixed tests are always same.

I understood the description but this is so hard!!
I thought once I found the longest ones (as many as int k) it would be so much simpler
but actually It's not. I have to consider same strings, same length,and given order of them at the same time.
I almost got the correct answer by using 7 while loop but I need more now. (I know it's my fault)

It seems my solution passed the sample test.
But when I click 'attempt' , the sample test in the final test is not passed.
Is there any difference between these two sample tests?

I don't know what this means..

Plz Don't mock! haha