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Events (Posted on 2005-02-10) Difficulty: 1 of 5
Suppose there were three events that could be done in any order. Let these events be A, B and C. There are a total of 6 possible ways the events can be performed.

However, this time, there is a restriction. B can only be performed after A. In other words, A must be performed before B can, and ACB is also accepted.

Your task is to find a general formula for X number of events, and Y number of restrictions.

None of the events is mentioned in more than one restriction.

No Solution Yet Submitted by wcaexqdz    
Rating: 2.0000 (4 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
Solution Solution | Comment 1 of 4
Since events appear at most in one restriction...

Each restriction halves the possible solutions, so the answer is X!/2^Y.

The maximum number of restrictions is X/2.
Edited on February 10, 2005, 2:33 pm
  Posted by e.g. on 2005-02-10 14:32:15

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