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Why is the 5th test case in "B. Flip the Bits" of "Codeforces Round #712 (Div. 2)" is impossible?

Revision en1, by vrintle, 2021-06-06 10:57:11

Hello everyone!

Here is the link to the problem: https://mirror.codeforces.com/contest/1504/problem/B

In the 5th test case, $$$A$$$ can be converted to $$$B$$$ as:

000111 -> [000111] -> 111000
111000 -> 11[10]00 -> 110100

As, both the prefix contains equal $$$1$$$ and $$$0$$$, so I think this is correct. But, the answer says, it is impossible to convert $$$A$$$ to $$$B$$$. Why?

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en1 English vrintle 2021-06-06 10:57:11 469 Initial revision (published)