self-quiz-ch2-principles-ans

# self-quiz-ch2-principles-ans - CS432, Algorithms Names:...

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CS432, Algorithms Names: Some problems for Chap. 2 lectures Answer the questions below before the end of class and turn it in. The results you give will not count toward your grade in the class. The purpose of this test is for me to get a feel for how well the class overall understands this material, and for you to see how well you understand this material. 1) Set up the formula for calculating the average case complexity for Sequential Search (AKA Linear Search) on an unsorted array. Assume that the "target" element is definitely in the array, but that there is a 50% chance it is in the first position (and equally likely in all other positions). Just set up the formula - you don't have to solve it. For position 1, we do one comparison so T(I) = 1. P(I) = 0.5. For each position i from 2 to n, we T(I) = i and P(I) is 0.5/(n-1). A ( n ) = 1 " 0.5 + (0.5 " i ( n # 1)) i = 2 n \$ 2) Argue that one cannot find the minimum element in an unsorted array of size n without doing at least n-1 comparisons.
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## This note was uploaded on 03/21/2010 for the course CS 4102 taught by Professor Horton during the Spring '10 term at UVA.

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