http://www.codechef.com/COOK56/problems/STRAB/
Can someone explain the dp approach except the one given in the editorial ? Also if someone know similar problems , please provide the link :) .
http://www.codechef.com/COOK56/problems/STRAB/
Can someone explain the dp approach except the one given in the editorial ? Also if someone know similar problems , please provide the link :) .
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In fact, you don't need dp in this problem.
Let's count the following thing (just using a loop over bitmasks): how many there are strings of length L than consist only of A and B and are good (not hated, i. e., don't contain any hated subword).
Now let's iterate over all possible positions of non-AB characters (again as a loop over bitmasks). Obviously, if there is any hated word, it will be between two two consecutive non-AB characters. So we can use the thing we calculated earlier to fill all characters between non-AB ones.
thanks ,it will be very helpful if you can you refer someone's implemented code ? sorry to bother , i got it :).
Nice solution, and it seems to be O(n2n) too (don't know why you got downvoted). Why is it not in the editorial?