DMOPC '19 Contest 3 P2 - Generating Names
View as PDFVeshy is trying to come up with a username for his new alt-account! Unfortunately, he is currently in a creative lull, so he has turned to permuting strings of lowercase letters of length to find a username. This was still not creative enough for Veshy, so he is currently trying to increase the number of potential candidate usernames by having
wildcard characters (
*) in his starting string before permuting. Since you are Veshy's absolute best friend, help him find the number of candidate usernames!
Constraints
For all subtasks:
Subtask 1 [10%]
Subtask 2 [10%]
Subtask 3 [20%]
Subtask 4 [60%]
No additional constraints.
Input Specification
The first line will have space-separated integers,
and
.
The following line will have a string composed of only lowercase alphabet characters and/or the character
*. There will be
*'s in the string.
Output Specification
Output the total number of possible permutations of the string.
Sample Input 1
2 1
b*
Sample Output 1
51
Explanation of Sample Output 1
There are different possibilities for the wildcard character. Out of these
possibilities,
result in
unique permutations (e.g.
ba → ba and ab, bc → bc and cb, etc.), and results in only
unique permutation (when the wildcard character is
b, to make bb). .
Sample Input 2
2 2
**
Sample Output 2
676
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