Answer Happy

Complete these stages of code
public class Question1 { //begin class
/**
*
* @param list
* @return the number of values that are even in
the list
* return 0 if list is null or empty
*/
public static int countEven(ArrayList<Integer> list) {
return 0;
}
/**
* @param n: assumed to be more than 0
* @param d, d >= 0 and d <= 9
* @return true if number n contains the digit
d, false otherwise
* you may assume that 0 itself doesn't contain ANY digit (not
even 0)
* NOTE: This method must be implemented recursively.
* hint: n%10 gives the last digit, n/10 gives the rest of
the number
*/
public static boolean containsDigitRecursive(int n, int d) {
return false;
}
/**
* @param list
* @return the sum of differences between even
and odd indices.
* return 0 if list is null
* for example,
* if list = [20, 50, 80, 60, 30], return
(20+80+30)-(50+60)=20
* if list = [20, 30], return -10
* if list = [40], return 40
*/
public static int
differenceEvenOddIndices(ArrayList<Integer> list) {
return 0;
}
/**
* @param str: assume it's not null
* @return the string with all spaces
removed
* for example,
* if str = "voila", return voila"
* if str = " a b c
d . ", return "abcd."
* if str = "", return ""
*/
public static String withoutSpacesRecursive(String str) {
if(str.isEmpty())
return"";
if(str.charAt(0) == ' ')
return withoutSpacesRecursive(str.substring(1));
return str.charAt(0) +
withoutSpacesRecursive(str.substring(1));
}
public class Question5 { //begin class
/**
* @param list1
* @param list2
* @return true if the two lists are mutually
reverse of each other, false otherwise
*/
public static boolean
areMutuallyReverse(ArrayList<Integer> list1,
ArrayList<Integer> list2) {
return false;
}
/**
* @param list
* @return reverse of the list
*/
public static ArrayList<Integer>
reverse(ArrayList<Integer> list) {
return"";
}