Monday, September 03, 2007

Recent Links 09/03/2007 -- Numerical Python Basics

Programming in R

Finding Duplicate Elements in an Array :: Phil! Gregory  Annotated

Now, suppose that the array is of length n and only contains positive
integers less than n. We can be sure (by the pigeonhole principle)
that there is at least one duplicate.
    So, how do we find the beginning of the cycle? The easiest approach is to
    use Floyd's cycle-finding algorithm. It works roughly like this:
    Start at the beginning of the sequence. Keep track of two values (call
    them ai and aj). At
    each step of the algorithm, move ai one step
    along the sequence, but move aj two steps. Stop
    when ai = aj.

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