Key to CSE142 Final Exam, Winter 2018

1.  Solution:
        44,22 [44, 77] 0
        44,22 [44, 77] 55
        22,22 77


2.      Original Array                  Final Array
        -----------------------------------------------------------------
        {1, 1, 3}                       [1, 2, 3]
        {2, 1, 2, 4}                    [2, 2, 3, 4]
        {6, 13, 0, 3, 7}                [6, 3, 3, 5, 7]
        {-1, 6, 3, 5, -3}               [-1, 1, 3, 0, -3]
        {7, 2, 3, 1, -3, 12}            [7, 5, 3, 0, 6, 2] 


3.  Solution:
        Diamond
        Ruby 1
        Emerald 2

        Emerald
        Ruby 1
        Emerald 2

        Emerald
        Emerald 1
        Emerald 2

        Garnet
        Garnet 1
        Emerald 2


4.  Two possible solutions appear below.
    
        public static int censorNames(Scanner fileScan) {
            int names = 0;
            
            while (fileScan.hasNext()) {
                names++;
                
                System.out.print(fileScan.next() + " ");
                String lname = fileScan.next();
                for (int i = 0; i < lname.length(); i++) {
                    System.out.print("X");
                }
                System.out.println();
            }
            return names;
        }
        
        public static int censorNames(Scanner fileScan) {
            int names = 0;
            boolean first = true;

            while (fileScan.hasNext()) {
                String token = fileScan.next();
                if (first) {
                    System.out.print(token + " ");
                    names++;
                } else {
                    for (int i = 0; i < token.length(); i++) {
                        System.out.print("X");
                    }
                    System.out.println();
                }
                first = !first;
            }
            return names;
        }


5.  One possible solution appears below.

        public static int analyzeParagraphs(Scanner input) {
            int max = 0;
            while (input.hasNextLine()) {
                String line = input.nextLine();
                int count = 0;
                while (!line.equals("<p>")) {
                    count++;
                    line = input.nextLine();
                }
                System.out.println(count + "-line paragraph");
                if (count > max) {
                    max = count;
                }
            }
            return max;
        }


6. Two possible solutions appear below.

       public static double[] getTotalValues(String sequence, double[] weights) {
          String nucs = "ACGT";
          double[] result = new double[4];
          
          int currWeight = 0;
          for (int i = 0; i < sequence.length(); i++) {
             int index = nucs.indexOf(sequence.charAt(i));
             if (index >= 0) {
                result[index] += weights[currWeight];
                currWeight++;
             }
          }
          
          return result;
       }
       
       public static double[] getTotalValues(String sequence, double[] weights) {
          double[] result = new double[4];
          
          String noJunk = sequence.replace("-", "");
          for (int i = 0; i < noJunk.length(); i++) {
             int index = -1;
             if (noJunk.charAt(i) == 'A') {
                index = 0;
             } else if (noJunk.charAt(i) == 'C') {
                index = 1;
             } else if (noJunk.charAt(i) == 'G') {
                index = 2;
             } else if (noJunk.charAt(i) == 'T') {
                index = 3;
             }
             if (index >= 0) {
                result[index] += weights[i];
             }
          }
          
          return result;
       }
    

7. Three possible solutions appear below.

        public static void split(ArrayList<Integer> list) {
            for (int i = 0; i < list.size(); i += 2) {
                int n = list.get(i);
                list.set(i, n / 2 + n % 2);
                list.add(i + 1, n / 2);
            }
        }
        
        public static void split(ArrayList<Integer> list) {
            for (int i = 0; i < list.size(); i += 2) {
                int n = list.remove(i);
                list.add(i, n / 2 + n % 2);
                list.add(i + 1, n / 2);
            }
        }
        
        public static void split(ArrayList<Integer> list) {
            int index = 0;
            while (index < list.size()) {   
                int n = list.get(i);
                if (n % 2 == 0) {
                    list.add(index, n / 2);
                    list.add(index, n / 2);
                    list.remove(index + 2); 
                } else {
                    list.add(index, n / 2);
                    list.add(index, n / 2 + 1);
                    list.remove(index + 2);
                }
                index += 2;
            }
        } 
    

8. One possible solution appears below.

        public class Panther extends Critter {
            private boolean hunting;
            private Random rand;
            
            public Panther() {
                hunting = false;
                rand = new Random();
            }
            
            public Color getColor() {
                if (hunting) {
                    return Color.RED;
                } else {
                    return Color.BLACK;
                }
            }
            
            public boolean eat() {
                boolean shouldEat = !hunting;
                hunting = true;
                return shouldEat;
            }
            
            public Attack fight(String opponent) {
                if (hunting) {
                    hunting = false;
                    return Attack.SCRATCH;
                } else {
                    return Attack.ROAR;
                }
            }
            
            public Direction getMove() {
                int check = rand.nextInt(4);
                if (check == 0) {
                    return Direction.NORTH;
                } else if (check == 1) {
                    return Direction.EAST;
                } else if (check == 2) {
                    return Direction.SOUTH;
                } else { // check == 3
                    return Direction.WEST;
                }
            }
        }
		
9. Three possible solutions appear below.

        public static int[] insertMiddle(int[] a, int[] b) {
            int[] result = new int[a.length + b.length];
            for (int i = 0; i < a.length / 2; i++) {
                result[i] = a[i];
            }
            
            for (int i = 0; i < b.length; i++) {
                result[i + a.length / 2] = b[i];
            }
            
            for (int i = a.length / 2; i < a.length; i++) {
                result [i + b.length] = a[i];
            }
            
            return result;
        }
        
        public static int[] insertMiddle(int[] a, int[] b) {
            int lengthA = a.length;
            int lengthB = b.length;
            int[] result = new int[lengthA + lengthB];
            for (int i = 0; i < result.length; i++) {
                if (i < lengthA / 2)
                    result[i] = a[i];
                else if (i < (lengthA / 2 + lengthB))
                    result[i] = b[i - lengthA / 2];
                else
                    result[i] = a[i - lengthB];
            }
            return result;
        }
        
        public static int[] insertMiddle(int[] a, int[] b) {
            int[] c = new int[a.length + b.length];
            int n = 0;
            
            for (int i = 0; i < a.length / 2; i++) {
                c[n] = a[i];
                n++;
            }
            
            for (int i = 0; i < b.length; i++) {
                c[n] = b[i];
                n++;
            }
            
            for (int i = a.length / 2; i < a.length; i++) {
                c[n] = a[i];
                n++;
            }
            return c;
        }
		
10. Three possible solutions appear below.

        public static boolean samePattern(String s1, String s2) {
            if (s1.length() != s2.length()) {
                return false;
            }
            for (int i = 0; i < s1.length(); i++) {
                for (int j = i + 1; j < s1.length(); j++) {
                    if (s1.charAt(i) == s1.charAt(j) &&
                    s2.charAt(i) != s2.charAt(j)) {
                        return false;
                    }
                    if (s2.charAt(i) == s2.charAt(j) &&
                    s1.charAt(i) != s1.charAt(j)) {
                        return false;
                    }
                }
            }
            return true;
        }
        
        public static boolean samePattern(String s1, String s2) {
            if (s1.length() != s2.length()) {
                return false;
            }
            for (int i = 0; i < s1.length(); i++) {
                if (s1.indexOf(s1.charAt(i)) != s2.indexOf(s2.charAt(i))) {
                    return false;
                }
            }
            return true;
        }

        public static boolean samePattern(String s1, String s2) {       
            if (s1.length() != s2.length()) {
                return false;
            }
            String chars1 = "";
            String chars2 = "";
            for (int i = 0; i < s1.length(); i++) {
                char ch1 = s1.charAt(i);
                char ch2 = s2.charAt(i);
                if (chars1.indexOf(ch1) != -1) {
                    if (chars1.indexOf(ch1) != chars2.indexOf(ch2)) {
                        return false;
                    }
                } else {
                    if (chars2.indexOf(ch2) != -1) {
                        return false;
                    }
                    chars1 += ch1;
                    chars2 += ch2;
                }
            }
            return true;
        }