Description: This method creates an array that is filled with all of the digits of nums.

Method Call	return value/output
digitsToArray( 523 )	{3, 2, 5}
digitsToArray(1267 )	{ 7 , 6 , 2,  1 }

public boolean allFactorsOfSum(int[] nums)

Description: This method returns true if each element ofnums is a factor of the sum of nums.

Method Call	return value/output
allFactorsOfSum( {6,1,2,3} )	true (because all of the elements are factors of the sum which is12)
allFactorsOfSum( 1,4,7)	false (because 7 is not a factor of the sum of this array which is 12)

public String[] doubleArr(String[] strs)

Description: This method returns a new version of strs with each element appearing twice.

Method Call	return value/output
doubleArr( {“a”,”b”,”c”} )	{“a”,”a”,”b”,”b”, “c” , “c”}
doubleArr( {“math”,”ware”,”house”,”.com” })	{“math”,”math”,”ware”,”ware”,”house”,”house”,”.com”, “.com”}

public boolean isThere(int[] nums, int num)

Description: This method returns true if num is an element nums.

Method Call	return value/output
isThere( {6,1,2,3}, 6)	true
isThere( {6,1,2,3}, 5 )	false

public int indexOf(int[] nums, int num)

Description: This method returns the index value of the first appearance of num or -1 if num is not an element of nums .

Method Call	return value/output
indexOf( {6,4 ,7,3, 4 }, 4)	1
indexOf( {6,4 7 ,3,2,7}, 7)	2
indexOf( {6,4 ,2,3}, 22)	-1

public int lastIndexOf(int[] nums, int num)

Description: This method returns the index value of the last appearance of num or -1 if num is not an element of nums .

Method Call	return value/output
lastIndexOf( {6, 4 ,7 ,3, 11, ,4}, 4)	5
lastIndexOf( {7, 6,4 , 7 ,3}, 7)	3
lastIndexOf( {6,4 ,2,3}, 22)	-1

public boolean isIncreasing(double[] nums)

Description: This method returns true if each element in nums is greater than the element to its left.

Method Call	return value/output
isIncreasing( {1,2,3,4 })	true
isIncreasing( {1,0 ,3,4 })	false
isIncreasing( {1,1, 2,3,4 })	false

public int largestSpan(int[] nums)

Description: This method returns the largest span of consecutive increasing numbers

Method Call	return value/output
largestSpan( {4, 3, 1, 2, 3 , 1} )	3
largestSpan( {4  , 3,  1 , 12 , 31 , 44 , 52 , 1} )	5
largestSpan( {9, 7, 8 , 12,4, 3, 0, 4 , 1)	3
largestSpan( {1, 0, 4, 5 , 3,  2, 8 , 9, 10, 12, 4, 3,  1 })	5

** int[] invert(int[] nums)

Description: This method ‘inverts’ an array by spliting the array in halves and ‘inverting’ each half. See sample calls to understand.

Method Call	return value/output
invert( {5 , 21, 5, 13,4 })	{4, 13, 5, 21, 5  }
invert( { 1, 2, 3, 4, 5,6  })	{ 6, 5, 4, 3, 2, 1}

** int[] shiftByN(int[] nums, int delta)

Description: This method returns the array with all digits shifted by delta . Any digits that are circulated off the end of the array should be returned to the other side. Note: delta could be positive or negative. Please keep in mind that Math.abs(delta) > nums.length could be possible 😉

Method Call	return value/output
shiftByN( {5 , 21, 13,4 } 1)	{ 4 , 5 , 21, 13 }
shiftByN( {5 , 21, 13, 4 , 11} 2)	{ 4 , 11 , 5 , 21, 13}
shiftByN( {5 , 21, 13, 4 } -1)	{ 21, 13, 4 , 5}
shiftByN( {5 , 21, 13, 4 ,7 } -2)	{ 13, 4 ,7 , 5 , 21}

** int[] add(int[] num1, int[] num2, int base) throws ArithmeticException@precondition 1 < base < 11
@precondition num1.length = 5 and num2.length = 5
@postcondition: the returned array has 5 elements representing the sum or an ArithmeticException is thrown

Description: This method attempts to replicate addition. Consider both num1 and num2 represent the five digits of a number. Each element in the array stores one of the digits. For instance, the number 143 would be represented as {0,0,1,4,3 }. Numbers can be in any base between 2 and 10 inclusive , and the number 10110₂ in binary would appear in an arrays as : {1, 0, 1 , 1, 0 } . Let’s assume the numbers are positive.You should return an array representing the digits of the sum of num1 and num2. If the number of digits in the sum exceeds the maximum number of digits (5) , you should throw an arithmetic exception as shown in the code below:

if(overFlowAdditionOccurred) throw new ArithmeticException("Addition Overflow Error");

1 2	if(overFlowAdditionOccurred)     throw new ArithmeticException("Addition Overflow Error");

Note: You may not use any kind of helper or utility methods that are built into pre-defined Java classes for converting numbers between bases. Only use techniques taught in this class.

Method Call	return value/output
add( {0,0,0 ,4,2},{0,0,0,5,1}, 10)	{0, 0, 0, 9, 3} ie (42 + 51 = 93)
add( {0, 0, 0 ,7,2},{0,0,0,5,1}, 10)	{0, 0 , 1 , 2, 3} ie (72 + 51 = 123)
add( {0, 0 , 0 , 1 , 1}, { 0 , 0 , 0 , 1 }, 2)	{0, 0 , 1 , 0 , 0} ie ( 112 + 12= 1002 )