 # CSCI A201/A597 and I210 Problem Set Five

Second semester 2000-2001

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Due date is

`Sat Mar 31 11:59pm`
Solutions to be posted here the following day, at noon.

 1 Write a method `static double scalarProduct(double[] a, double[] b)` that computes the scalar product of two mathematical vectors (represented as arrays). The scalar product is: a0b0 + a1b1 + ... + an-1bn-1

 2 Write a method that computes the alternating sum of all elements in an array. For example, if `alternatingSum` is called with an array containing 1   4   9   16   9   7   4   9   11 Then it computes 1 - 4 + 9 - 16 + 9 - 7 + 4 - 9 + 11 which is, of course, `-2`.

 3 Write a method `reverse` that reverses the sequence of elements in an array. For example, if `reverse` is called with an array containing 1   4   9   16   9   7   4   9   11 then the array is changed to 11   9   4   7   9   16   9   4   1

 4 Write a method `public static int[] append(int[] a, int[] b) ` that appends one array after another. For example, if `a` is 1   4   9   16    and `b` is 9   7   4   9   11 then `append` returns the array 1   4   9   16   9   7   4   9   11

 5 Write a predicate method `public static boolean equals(int[] a, int[] b)` that checks whether two arrays have the same elements in the same order.

 6 Write a predicate method `public static boolean sameSet(int[] a, int[] b)` that checks whether two arrays have the same elements in some order, ignoring multiplicities. For example, the two arrays 1   4   9   16   9   7   4   9   11 and 11   11   7   9   16   4   1 would be considered to have the same set. You will probably need one or more helper methods.

 7 Write a predicate method `public static boolean sameElements(int[] a, int[] b)` that checks whether two arrays have the same elements in some order, with the same multiplicities. For example, 1   4   9   16   9   7   4   9   11 and 11   1   4   9   16   9   7   4   9 would be considered to have the same elements, but 1   4   9   16   9   7   4   9   11 and 11   11   7   9   16   4   1 would not. You will probably need one or more helper methods.

Last updated: Mar 8, 2000 by Adrian German for A201