## Editorial for JDCC '16 Contest 3 P5 - CPT Elections

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**only**when stuck, and**not to copy-paste code from it**. Please be respectful to the problem author and editorialist.**Submitting an official solution before solving the problem yourself is a bannable offence.**Author:

This problem is almost identical to Bertrand's Ballot Problem, and is solved in a similar way.

The answer to the problem is given by the formula , where represents the votes that André received, represents the votes that Bertrand received and is the minimum difference between their votes. Note that is the choose function. Here is a detailed proof of the formula.

To calculate the answer, use the property when calculating the choose function.

For the division, use the property , where is the modular inverse of .

**Time Complexity:**
, due to the fact that the complexity of the choose function is

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