Project 1 Added clarifications for stringValue and expValue

Changelog

    • Feb 10: Added clarifications for stringValue and expValue



Description

The purpose of this assignment is to get practice with strings, arrays, loops and dynamic memory allocation. 

Submission

Submission instructions are as follows:

    1. Name your file P1.java and upload it to Gradescope using the following link https://www.gradescope.com/courses/498183/assignments/2626464

    2. Download the file you just uploaded to Gradescope and compile/run it to verify that the upload was correct

    3. Make a backup of your file on OneDrive using your GMU account

If you skip steps 2 and 3 and your submission is missing the proper file(s), there won’t be a way to verify your work and you will get zero points.

1 

Testing

We won’t be using testers in CS211. The goal is to help you put more focus on writing logically correct programs instead of trying to pass certain tests only. As a programmer, you must learn how to test your code on your own and you must also develop the ability to discover the corner cases that need to be tested.



Task

You will implement the following methods in Java. Every method is self-contained; there are no dependencies among the methods. You’re free to create helper methods if you want though. Make sure you do not modify the method signatures that are provided, otherwise your code will not pass the compliance checks and we won’t be able to grade it.

 
public static int stringValue(String word)

It returns the value of a string which is the sum of the values of its characters. The value of each character is the ASCII code of the character (e.g. A has a value of 65, B has a value of 66, a has a value of 97, etc.) with a few exceptions:

    • Double-letters (e.g. ee, mm, ll, tt, etc.) are valued once, not twice. Double-letters only, not triple, quadruple, etc. And letters only, not numbers or special characters.

    • The space character has a value of zero

    • The value of each numeric character is multiplied by the largest value of the non-numeric characters in the string (assume that the string will always contain at least one non-numeric character).

To simplify things a bit, assume that the word will not include, and your program will not be tested with, any characters that have an ASCII code lower than 40 or higher than 123.

Examples:

word
return
solution
Mason
510
77+97+115+111+110
Ma son
510
77+97+0+115+111+110
mass
321
109+97+115
massss
436
109+97+115+115
masssss
551
109+97+115+115+115
50 Cent
12110
53*116+48*116+0+67+101+110+116




public static double expValue(int x, double precision)

The calculation of the ex function appears a lot in applications and it’s considered quite an expensive computation. One way to calculate it is with the following formula:

ex=∑k∞=0
xk
=1+x +
x2
+
x3
+
x4
+...

k !









2
6
24


As you can tell, this is an infinite series. After some point though, the precision of the result doesn’t improve much. Therefore, we can stop adding terms when the improvement is smaller than the precision parameter which is a positive number. In other words, if the effect of adding a certain term is smaller that the precision, then we do not add this term and we stop the series. The method returns the sum of the series.

For the expValue method, you may not use any of the exponential methods of the Math class.


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public static int mirrorNum(int num)

The method accepts an integer and returns the mirrored integer. In case of a negative number, it retains the sign.

For the mirrorNum method, you may not use any classes from any package, not even the Math and String classes.

Examples:


num    return


4    4

98014    41089

-593    -395

12300    321











public static boolean raisedNum(long num)

There are some numbers whose value is the sum of x y+ y x where x and y are integers greater than 1. Let's call these numbers raised numbers. Write a method that accepts a long and returns true if the number is raised, and false otherwise.

Examples:


input    return    solution


    • false

17
true
23 +32
593
true
92 +29
1125
false












4
public static int[][] smallestSubarray(int[][] array, int sum)

It takes a rectangular array and returns a square-size subarray of it whose values have a sum that is equal or larger to sum. A subarray can’t be smaller than 2x2. If there are more than one square-size subarrays that satisfy the requirements, the method must return the square that has the smallest size. If two or more equally-sized squares satisfy the requirements, it must return the square whose values have the highest sum. Assume that the sum has such a value that always warrants a solution (i.e. no need to check or worry about this).


Examples:


array    sum    return


{{0,1,2},{-4,5,6},{7,8,3}}    5    {{5,6},{8,3}}

{{0,1,2},{-4,5,6},{7,8,3}}    23    {{0,1,2},{-4,5,6},{7,8,3}}

















public static void replaceElement(int[][] array, int elem, int[] newElem)

It takes a two-dimensional array and modifies it in-place (i.e. the method doesn’t return anything). Every occurrence of elem is replaced by the items contained in newElem. The modification must happen in-place, i.e. the memory address of the whole array must remain the same; but the memory addresses of its rows can change of course.

Examples:


array before method invocation
elem
newElem
array after method invocation








{{1,2,3,4,5},{6,7,8}}
2
{0}
{{1,0,3,4,5},{6,7,8}}
{{1,2,3,4,5},{5,4,3,2}}
5
{-5,5}
{{1,2,3,4,-5,5},{-5,5,4,3,2}}
{{0,1,2,3,4,5},{5,4,3,4}}
4
{1,2,3}
{{0,1,2,3,1,2,3,5},{5,1,2,3,3,1,2,3}}














5
public static int[][] removeDuplicates(int[][] array)

It takes as input a two-dimensional array and returns a new two-dimensional array where every sequence of duplicate numbers is replaced by a single occurrence of the respective number. Keep in mind that duplicate numbers can extend in more than one rows though.

Examples:


input array    returned array


{{1,2,3,4,5},{6,7,8,9}}    {{1,2,3,4,5},{6,7,8,9}}

{{1,2,2,2,3,4,5,5},{6,7,8,8,8,9}}    {{1,2,3,4,5},{6,7,8,9}}

{{1,2,2,2,3,4,5,5},{5,5,5,5},{5,5,9}}    {{1,2,3,4,5},{9}}








public static int[] vortex(int[][] array)

It takes as input a two-dimensional rectangular array, traverses its contents in a clockwise spiral order starting from index (0,0), and returns the result as a single-dimensional array.

















Examples:


input array    returned array


{{1,2,3},{4,5,6},{7,8,9}}    {1,2,3,6,9,8,7,4,5}

{{1,2},{3,4},{5,6},{7,8},{9,10}}    {1,2,4,6,8,10,9,7,5,3}

{{1,2,3,4,5},{6,7,8,9,10},{11,12,13,14,15}, {1,2,3,4,5,10,15,20,19,18,17,16,11,6,7,8,9,14,13,12} {16,17,18,19,20}}




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