So, it's still WA I'm very disappointed. Can u show me ur code ? I don't understand what wrong with ithelloneo wrote:

Is that valid input..?

My AC code returns "_AB_______"

Anyway, your approach look correct..

But, your code is missing '\n' after the last case.. (when the output of the last case is not '!')

And, if there multi answer allowed, what kind of case I should to choose for my answer ?

And, what do u think about next test?

A1 2;

C1 1;

B1 12;

B1 1234;

According to the UVA toolkit the answer must be equal to "_CABB_____";

now I'm going to research this test case more deeply.

User 1 comes to solve him one problem "A", he can to do it only on 2nd computer,

then user 2 has one problem "C" and he can solve it only on first computer,

user 3, have one problem B , and cans solve it only on first r second machine,

user 4, as user 3, also has the same "B", but he can solve it on 1,2,3,4 computers.

according to the uva toolkits answer user 3 can solves his problem on computer 3 & 4 also, it looks naturally if user 3 and 4 has problems identical "B".

Ok, lets try to look on the next two test cases:

A1 2;

C1 1;

V1 234;

B1 2345;

B1 3;

and

A1 2;

C1 1;

V1 23;

B1 2345;

B1 3;

Who can explain to me why first has answer "_CABVB____" and second has "_CAVBB____" according to the UVA toolkit?

Who has solved this damned PROBLEM ?

So, i'm interested in input data from the UVA server, how i can get it ?