Problem of the Day

Problem:

The static method convert is designed to use a one-dimensional Array of positive integers for filling a two-dimensional Array of the same integers arranged into a specified number of rows and columns, and returning that result. If there are insufficient values in the one-dimensional array to fill the two-D array, values of -1 are placed in the extra locations. If there are too many values in the one-dimensional array to fit into the specified two-dimensional array, those extra values are left out of the two-dimensional result.

A partial listing of the method is given here.

/**
 * Converts a 1-dimensional Array to a 2-dimensional with the
 * given number of rows and cols. If the 1-D Array is not large
 * enough to fill the 2-d Array, values of -1 are used for the 
 * extra values. If the 1-dimensional Array is to large to fit 
 * into the specified 2-D Array, the extra values are left out.
 * @param arr a 1-D integer Array
 * @param rows the number of rows in the 2-d Array to be returned
 * @param cols the number of cols in the 2-d Array to be returned
 * PRECONDITION: rows and cols >= 1
 */
public static int[][] convert(int[] arr, int rows, int cols)
{
    int[][] result = new int[rows][cols];

    /* missing code */

    return result;
}

Which of the following can be used to replace /* missing code */ so that the method will work as described?

1. 
   

   int i = 0;
   for (int r = 0; r < rows; r++) {
       for (int c = 0; c < cols; c++) {
           if (i < arr.length)
           {
               result[r][c] = arr[i];
               i++;
           }
           else
           {
               result[r][c] = -1;
           }
       }
   }

2. 
   

   int i = 0;
   for (int r = 0; r < rows; r++) {
       for (int c = 0; c < cols; c++) {
           if (i < rows * cols)
           {
               result[r][c] = arr[i];
               i++;
           }
           else
           {
               result[r][c] = -1;
           }
       }
   }

3. 
   

   int r = 0;
   int c = 0;
   int i = 0;
   while (i < rows * cols) {
       if (i < arr.length)
           result[r][c] = arr[i];
       else
           result[r][c] = -1;
       i += 1;
       r = i / cols;
       c = i % cols;
   }
   return result;

1. I only
2. II only
3. III only
4. I and II only
5. I and III only

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