2015 FRQ

//part A
public static int arraySum(int[] arr)
{
   int sum = 0;

   for(int n : arr)
     sum += n;

   return sum;
}

//part B
public static int[] rowSums(int[][] arr2D)
{
   int[] sums = new int[arr2D.length];

   for(int i = 0; i < sums.length; i++)
   {
      sums[i] = arraySum(arr2D[i]);
   }

   return sums;
}

//part C
public static boolean isDiverse(int[][] arr2D)
{
   int[] sums = rowSums(arr2D);

   for(int i = 0; i < sums.length; i++)
      for(int j = i+1; j < sums.length; j++)
         if(sums[i] == sums[j])
            return false;

   return true;
}

public class HiddenWord 
{
   private String hidden;

   public HiddenWord(String h) 
   {
     hidden = h;
   }

   public String getHint(String hint) 
   {
     String r = "";

     for(int i = 0; i < hint.length(); i++) 
     {
       if(hint.charAt(i) == hidden.charAt(i))
         r += ""+hint.charAt(i);
       else if(hidden.indexOf(hint.charAt(i)) > -1)
         r += "+";
       else
         r += "*";
     }

     return r;
   }
}

public class IntByReference {
    private int value;

    public IntByReference(Integer value) {
        this.value = value;
    }

    public String toString() {
        return (String.format("%d", this.value));
    }

    public void swapToLowHighOrder(IntByReference i) {
        if (this.value > i.value) {
            int tmp = this.value;
            this.value = i.value;
            i.value = tmp;
        }
    }

    public static void swapper(int n0, int n1) {
        IntByReference a = new IntByReference(n0);
        IntByReference b = new IntByReference(n1);
        System.out.println("Before: " + a + " " + b);
        a.swapToLowHighOrder(b);  // conditionally build swap method to change values of a, b
        System.out.println("After: " + a + " " + b);
        System.out.println();
    }

    public static void main(String[] ags) {
        IntByReference.swapper(21, 16);
        IntByReference.swapper(16, 21);
        IntByReference.swapper(16, -1);
    }

}
IntByReference.main(null);

Before: 21 16
After: 16 21

Before: 16 21
After: 16 21

Before: 16 -1
After: -1 16